Entomology

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A Study of the Ixodid Ticks of Northern Florida, Including the Biology and Life History of Ixodes scapularis Say (Ixodidae: Acarina)
(1953) Rogers, Andrew J.; Cory, Ernest N.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
On the Biology and Control of the North American Chestnut Weevils
(1956) Johnson, Warren T.; Cory, E.N.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
Curculio auriger (Casey) and Curculio proboscideus Fab. are indigenous North American nut weevils and attack only the fruits of chestnut and chinquapin. Their natural distribution occurs over the same geographical areas that the American chestnut was found. Since the destruction of most of the native chestnut trees by chestnut blight, Endothia parasitica (Murr.), the weevils have been able to survive on scattered plantings of oriental chestnuts which are resistant to blight, from a few native chestnut trees partially resistant and from the coppice growth of old chestnut stumps. Rearing of both species in the field was accomplished by the use of soil cages set into the ground to a depth of 12 inches. Adult behavior was studied in large cages that completely covered the tree. Chestnut weevils lay their eggs in the kernel. The eggs of C. auriger hatch in about eight days and those of C. proboscideus hatch in about 10 days under the conditions in central Maryland. There are four larval instars in each species and these are described and illustrated. Head characters were found that will separate the species and the instars. C. auriger completes its larval development in 21 days while it takes 30 days for Q. proboscideus. The pupae of both species are of' the exerate type and may be separated by the presence of two small bristles on the beak, near the insertion of the antennae, of C. auriger. These bristles are lacking in C. proboscideus. The usual life cycle of C. auriger is two years. The life cycle of C. proboscideus is usually one year. A few individuals of each species require an additional year to complete their cycle. The adult C. auriger issues from the ground in May and feeds on the chestnut catkins. After the catkins wither they disperse and are not seen again until the chestnuts are nearing maturity. C. proboscideus issues from the ground late in July and may be seen in the trees a few days after emergence. The male genitalia were studied for taxonomic characters. These characters are sufficiently clear so that the two chestnut weevils may be identified thereby. Two species of internal insect parasites were found. Myiophasia nigrifrons Tns., a tachinid fly, was reared from the larvae of both species of' chestnut weevils and was observed in its larval stage within the body cavity of the chestnut weevil larva. Urosigalphus armatus Ashm. is a braconid parasite and was found only in the larvae of Q. prohoscideus. Chemical control studies have shown that the adult stage is the most susceptible to insecticides. Preliminary tests with heptachlor, applied at the rate of six to eight pounds of the chemical per acre, as a spray or dust to the ground cover under the trees, have given excellent results for the control of chestnut weevils.
Ecological Studies of Black Flies in Two Maryland Counties (Diptera:Simuliidae)
(1957) McComb, William E.; Bickley, William E.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
The Genera Hemiberlesia and Abgrallaspis in North America with Emphasis on Host Relationships in the H. Howard (Cockerell) Complex (Homoptera: Coccoidea: Diaspididae)
(1960) Davidson, John Angus Sr.; Bickley, William E.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, MD)
The work reported consists of revisionary studies of Hemiberlesia Cockerell 1897 and Abgrallaspis Balachowsky 1948 in North America. The interpretation of North America is that of Ferris (1937), "all the mainland from the Arctic regions to and including the Panama Canal Zone." According to Ferris (1942), Hemiberlesia contained 15 species. As a result of this study, only eight of these species are here referred to Hemiberlesia. They are: rapax (Comstock), lataniae (Signoret), popularum (Marlatt), ignobilis Ferris, cupressi (Cockerell), diffinis (Newstead), candidula (Cockerell), and palmae (Cockerell). The species H. coniferarum (Cockerell) is newly assigned having previously been placed in Diaspidiotus Berlese and Leonardi, by Ferris. A tenth species, H. pseudorapax McKenzie, was assigned to this genus by its author. Seven of the 15 species have been assigned to Abgrallaspis. Both these genera appear to be North American in origin. Abgrallaspis was originally created for six species. Three of these occur in North America and were transferred from Hemiberlesia by Balachowsky. They are: palmae (Cockerell), degeneratus (Leonardi), and cyanophylli (Signoret). The last named species was designated as the genotype. Balachowsky (1953) later reassigned palmae to Hemiberlesia and transferred four more North American Hemiberlesia species to Abgrallaspis, namely, howardi (Cockerell), comstocki (Johnson), coloratus (Cockerell), and fraxini (McKenzie). A study of these species in the National Coccoid Collection revealed a complex centering about A. howardi as conceived by Ferris (1938). Usual morphological comparisons of slide mounted adult females failed to yield results, therefore, host transfer experiments were undertaken. A population of "howardi" of Ferris was secured on pachysandra. A total of 2,700 individual crawler transfers were then made to 20 different host plants. These hosts had been chosen because a preliminary study indicated unusual character variation in specimens collected from them. Fourteen of the test hosts (largely ornamentals) were later found to be infested with 14 to 54 per cent of the transferred crawlers. These crawlers were allowed to mature. Adult females were then collected and mounted for study. Six host plant species were completely unacceptable to infestation by the transferred crawlers. Five of these were plum, pear, peach, apple, and pine. A. howardi was described from plum in Colorado, and later recorded from such hosts as pear, peach, and apple. A study of the species Ferris synonymized with A. howardi revealed the test population to be A. townsendi (Cockerell), which was described from an unknown host in Mexico, and later recorded from a long list of ornamentals primarily in the southern and eastern United States. This species is redescribed and the name revalidated. A table is presented showing the variations found in salient taxonomic characters of A. townsendi collected from 14 different experimental host plants. Important variations in the size of the second lobes of A. townsendi were recorded. Second lobe reduction from three-fourths the length of the median lobes to mere hyaline points was observed. Specimens in the last category strongly resemble Diaspidiotus ancylus (Putnam). Aside from these second lobe variations, A. townsendi is a relatively stable species from the standpoint of host determined morphological variables. Avocado was the sixth test host on which transferred crawlers would not develop. Long series of scales from this host are present in the National Collection. They were collected from avocado fruit in quarantine at Texas, from Mexico. This species, A. perseus Davidson, is described as new herein. As here understood for North America, Abgrallaspis contains 13 species. Six were placed in this genus by Balachowsky, and seven by the writer. The last are: flabellata (Ferris) from Hemiberlesia; quercicola (Ferris) from Hemiberlesia; mendax (McKenzie) from Hemiberlesia; oxycoccus (Woglum) from Aspidaspis Ferris; ithacae (Ferris) from Aspidaspis; perseus Davidson as a new species; and townsendi (Cockerell) as a revalidated name. A brief presentation of materials and methods utilized in the host transfer experiments is followed by a discussion of the structural characters used in this work. Descriptions of Hemiberlesia and Abgrallaspis are accompanied by keys and descriptions to all the species in North America. Figures of adult female pygidial characters and scale coverings are provided for all species considered in these two genera.
The Effect of Plant Nutrition on the Reproductive Rate and Susceptibility to Malathion of Two Strains of the Two-Spotted Spider Mite, Tetranychus telarius (L.)
(1960) Henneberry, Thomas J.; Bickley, William E.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
Studies were conducted to determine the effect of plant nutrition on the reproductive rate and susceptibility to malathion of two strains of the two-spotted spider mite. The two strains of mites used as test organisms are characterized by their widely different levels of susceptibility to phosphate acaricides. Lima bean plants were grown in quartz sand and supplied nutrient solutions containing varying levels of nitrogen, phosphorus and potassium. Total nitrogen and total water soluble carbohydrate in the host plant tissue were determined by standard methods. Correlation analysis with the number of mite progeny and results of leaf analyses were conducted. The effects of plant nutrition on susceptibility to malathion of the two mite strains were determined by comparing per cent mortality data of mites from plants supplied the various nutrient solutions, Dosage-mortality responses of the two mite strains were also determined for mites of both strains from plants supplied nutrient solutions producing the greatest response in susceptibility. The reproductive rate of both strains increased as the supply and absorption of nitrogen increased. However, in studies with the resistant mite, a reduction in the number of progeny occurred on plants supplied the highest nitrogen level. The number of progeny of the malathion nonresistant mite were significantly correlated to increased nitrogen absorption. Increased reproductive rate of both strains was correlated to the carbohydrate present in the leaf tissue. When carbohydrate content in the leaf tissue was increased along with an increase in nitrogen supply and absorption the mite reproductive rate also increased. At still higher levels of nitrogen supply and absorption, carbohydrate content of leaf tissue decreased and the mite reproductive rate was depressed or failed to increase, The malathion non-resistant mite appeared more responsive to plants deficient in nitrogen than the resistant mite, On plants supplied the low nitrogen nutrient solutions, non-resistant mites failed to subsist, while the resistant mites maintained relatively high populations. The malathion non-resistant mite also produced more progeny on plants when phosphorus supply was increased. Populations of the resistant mite increased at higher levels of potassium. Phosphorus and potassium supply alone and in combination with certain levels of nitrogen affected nitrogen absorption and the relative amounts of carbohydrate present in the leaf tissue. Increasing the nitrogen supply to host plants resulted in increased susceptibility of the resistant mite to malathion. The non-resistant mite was more responsive to variations in phosphorus supply of host plants. A decrease in susceptibility followed an increase in phosphorus supply.
Studies on the Physiology of Hemolymph Coagulation in Perioplaneta Americana (L.)
(1964) Wheeler, Ronald Earl; Jones, Jack Colvard; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
In the cockroach, Periplaneta americana (L.), hemolymph coagulation (a) is inhibited for as long as 30 minut es at 0° to 4°c, (b) is initiated at 5°c, (c) is permanently inhibited at 60°c, and (d) takes place in 6 distinct stages. Hemocyte agglutination and transformation is inhibited at 0° to 4°C, is permanently prevented at 55°c, and is independent of plasmal factors. Live plasmatocytes, granular hemocytes, and cystocytes are structurally identical, but differ functionally in their capacity to phagocytize and in their fragility. The cystocyte's primary function is the initiation of coagulation and/or precipitation of the plasma by ejecting cytoplasmic material, including mitochondria, into the surrounding plasma. Hemocyte-free plasma will not spontaneously precipitate, but requires either ionic calcium released from transforming hemocytes, and/or material from exploded cystocyte mitochondria . Substances inside mitochondria may well be t he source of a coagulation-inducing substance that initiates plasma precipitation and veil formation. Substances involved in P. americana coagulation are present in the plasma of 9 other species of cockroach which react to P. americana cystocytes. Substances in the plasma of Tenebrio molitor, Galleria mellonella, or Rhodnius prolixus do not precipitate in the presence of P. americana cystocytes. The amount and/or effectiveness of a coagulation-inducing substance released from cystocytes presumably determines the degree of plasma precipitation. Physiologically active substances contained in and/or released from the corpora allata and c. cardiaca, but lacking in the brain, may regulate the percentage of circulating cystocytes, thereby influencing the coagulability of the hemolymph.
Biting Midges of the Genus Culicoides (Diptera: Ceratopogonidae) from Southwest Asia
(1977) Navai, Shahin; Messersmith, Donald H.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
A study was made of the Southwest Asian species of the genus Culicoides Latreille 1809 from six countries: Afghanistan, Iran, Israel, Pakistan, Saudi Arabia and Turkey. Thirty-eight species of Culicoides belonging to seven subgenera: Trithecoides, Pontoculicoides, Avaritia, Culicoides, Oecacta, Beltranmyia and Monoculicoides are described and illustrated. A key is provided to the subgenera and slide mounted species of both sexes. Seven new species are described.
The Bee Louse, Braula coeca Nitzsch, its Distribution and Biology on Honey Bees
(1978) Smith, Irving Barton Jr.; Caron, Dewey M.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
Bee lice were found in 28% of Maryland apiaries and 18% of the colonies examined. In apiaries with lice, 50% of the colonies contained lice. Laboratory tests demonstrated that bee lice had no preference between 1, 5, 15, and 30 day old honey bee (Apis mellifera L.) workers at 25° while there was a preference for 1 day old workers at 34° C. Lice preferred young drones over old drones and virgin and mated queens over young drones at 25 and 34° C. Lice preferred virgin queens over old drones at 25° C while no preference was observed at 24° C. Mated queens were preferred over old drones at 25 and 34° C. There was a preference of lice for foraging age workers over old drones at 25° C while there was no preference at 34° C. Lice preferred both virgin and mated queens over random age workers at 25 and 34° C. Louse larval tunnels were numerous in nucs (4 frame honey bee colonies) stocked with lice from May through August corresponding with periods of nectar flow when bees were capping honey. In field colonies, louse populations decreased in the late spring to a low in early June. During July and after, populations of lice rose with the emergence of new lice. Few immature and adult lice were observed in control nucs having similar populations of bees. In nucs, 1 or more lice were observed on 24% of the queens between August and December. Only 2% of the virgin queens contained lice during the same period. In field colonies, 62% of the queens examined from June through the rest of the season harbored lice; 58% of these lice were pale in color indicating they were less than 1 day old. One louse was observed on 98.6% of the workers with lice, while 1.2% harbored 2 lice and 0.2% had 3 lice; 4 .2% of the lice were on drones. A single bee louse was observed on 3,092 foraging honey bees sampled. One-hundred-seventeen lice were collected on 14,459 bees collected from the brood nest of the same hives. Control samples indicated a 14 to 15% loss of lice during sampling. Tests demonstrated that during visual observations of lice on bees only 49% of the lice present were observed. Fluctuation in louse population levels were similar to those found elsewhere in this study.
Biosystematics and the evolution of gall formation in hackberry psyllids Pachypsylla (Insecta: Homoptera: Psylloidea: Psyllidae)
(1995) Yang, Man-Miao; Mitter, Charles; Miller, Douglass R.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
This dissertation is a study of the phylogeny and evolutionary biology of gall formation in psyllids of the subfamily Spondyliaspidinae, with particular focus on North American hackberry gallers in the genus Pachypsylla. Species in this genus produce a variety of gall types on the leaves, petioles, buds and twigs of their hosts, four species of Celtis subgen. Euceltis (Ulmaceae). The homogeneity of adult morphology in Pachypsylla, contrasted to the great variation in gall morphology and phenology, has led to much difficulty in delimiting species. Chapter I investigates species limits as related to gall type and host specificity in Pachypsylla. Strong differences in allozymes, morphology and life history confirm that leaf, petiole, bud and twig gallers belong to different species or species groups. Different leaf gall morphs probably also represent different species, as evidenced by significant allozyme frequency differences among sympatric pairs of gall morphs, consistent frequency difference between co-occurring morphs across localities, and discrete differences in gall type between progenies of individual females. Differences in allozymes, female phenology, adult and nymphal coloration, as well as laboratory rearings and field manipulations, show that side cell individuals within two nipple gall types represent an inquiline sibling species (Chapter II). Chapter III is an analysis of phylogenetic relationships within Pachypsylla, based on allozyme, morphological, life history and chromosome characters. Galler populations attacking the same plant tissue form monophyletic groups. The leaf galler morphs are little diverged, and phylogenetic relationships among them are unclear. Populations of inquilines from two different gall types appear closely related; the inquiline appears to be derived from a gall-forming ancestor. Phylogenetic relationships among gallers on different plant parts are consistent with an evolutionary sequence of gall position from leaf to petiole to bud to twig. Chapter IV is a morphological study of phylogenetic relationships within Spondyliaspidinae. The tribe Pachypsyllini, including Pachypsylla and two related Celtis feeders, is monophyletic. The tree favors the hypothesis of Burckhardt over that of White and Hodkinson. The distribution of lerp and gall formation is shown to be non-random within Spondyliaspidinae.
INTEGRATED MANAGEMENT OF THE BOXWOOD LEAFMINER
(1999) d'Eustachio, Gabriel John; Raupp, Michael J.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
Landscape managers need durable, effective, and safe methods for controlling key pests of valued plants in both landscape and nursery settings. The boxwood leafminer (Monarthropalpus flavus, Diptera: Cecidomyiidae) is a serious pest of boxwoods. Boxwoods (Buxus sp.) are a key plant in suburban Maryland landscapes. They are the second most common woody ornamental plant in these settings. In a recent study almost 43% of boxwoods surveyed required treatment for leafminer infestation. Boxwood leafminers also pose a serious problem in historical gardens, such as Longwood Gardens, PA, Dumbarton Oaks and the US National Arboretum in Washington, DC. At the present time, there is a lack of a comprehensive, environmentally sound, management program for the boxwood leafminer. The first step toward an effective management strategy is a better understanding of the boxwood leafminer's life cycle. Over the summers of 1994-1995, leafminer populations were surveyed and life cycles documented and correlated with growing degree days. The first growing degree day developmental chart for boxwood leafminer was developed. Various pesticides were tested in 1995. Different chemicals and application times were evaluated for control of both adults and larvae. At present it appears that application of a translaminar pesticide such as Avid or Merit at adult emergence (growing degree day 352) provides the best control. Resistant cultivars appear to be the most durable, simplest method to control the leafminer. Some cultivars.are highly resistant to boxwood leafminer attack while others are highly susceptible. The third goal of my project was to identify resistant cultivars. This was accomplished by first observing natural variation in leafminer populations in the field. Next I caged ovipositing adults on terminal branches of various cultivars of boxwood, and measured survival of larvae. All cultivars received heavy oviposition with equal frequency, although survival rates were very different. Finally, I tested the hypothesis that leafminers could discriminate among resistant and susceptible cultivars. To test this emerging adults were caged with different cultivars of boxwood and allowed to select plants for oviposition. Plants were then analyzed to determine acceptance of various host plants. I found that although survival on different cultivars can vary dramatically, leafminers were unable to distinguish between suitable and unsuitable host plants.
Characterization of Female Specific Salivary Gland Glycoproteins of Anopheles Gambiae and their Interaction with Plasmodium Berghei Sporozoites
(1999) Bartels-Andrews, Lucy; Sina, Barbara; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md)
This study investigated the female specific salivary gland glycoproteins of Anopheles gambiae mosquitoes and their possible role in malaria sporozoite invasion of the salivary glands. Male and female Anopheles gambiae salivary gland proteins were analyzed by western blot with various lectins to identify glycoproteins that are specific to the female salivary glands. At least, 14 female glycoproteins were detected by specific lectins in the female glands but not in the male glands and were designated as female specific. The different morphological regions of the female salivary glands showed distinct lectin binding characteristics with the distal lateral and the median regions displaying the most glycoproteins. The lectins that identified the most female specific glycoproteins were tested in a transplantation assay to determine their effect on Plasmodium berghei sporozoite invasion of the salivary glands. The transplantation procedure was similar to that reported by Rosenberg (1985) with some improvements which resulted in 90-95% mosquito survival after the transplant procedure. Up to 3% of the total sporozoites that invaded the salivary glands were found in the transplanted glands. The results of our analyses showed that the lectins soybean agglutinin (SBA) and wheat germ agglutinin (WGA) significantly reduced sporozoite invasion while the lectins Concanavalin agglutinin (Con A) and Dolichos biflorus agglutinin (DBA) had no effect on sporozoite invasion. The pattern of distribution of glycoconjugates on the female salivary glands showed that Con A bound uniformly and moderately to the whole gland while SBA and WGA bound intensely to the distal ends of the median and lateral lobes of the salivary glands. The binding pattern of SBA and WGA corresponds to the regions of the female glands where sporozoites enter the glands. These results suggest that malaria sporozoites interact with specific carbohydrate molecules on the salivary glands for invasion. To characterize salivary gland surface glycoproteins that may be involved in sporozoite invasion, salivary gland surface proteins were labeled by the biotinylation reagent sulfosuccinimidyl 6-biotinamido hexanoate, followed by lectin affinity chromatography. 7 of the labeled surface glycoproteins detected by sporozoite blocking lectins (SBA and WGA) had molecular weights corresponding to female specific glycoproteins. These female specific salivary gland surface glycoproteins are of potential interest in studying sporozoite interaction with salivary gland glycoconjugates. To determine that malaria sporozoites capable of invading mosquito salivary glands interact with carbohydrate molecules, hemagglutination and carbohydrate binding assays were conducted using sporozoites isolated from infected mosquito midguts. The results obtained suggest that interaction of sporozoites with mosquito salivary gland glycoconjugates may be mediated by sporozoite proteins other than the circumsporozoite protein, the major protein covering the surface of sporozoites.
Two ant species (Hymenoptera: Formicidae) new to the Hawaiian Islands
(Bishop Museum Occasional Papers, 2003) Gruner, Daniel; Heu, Ron; Chun, Marianne
Two new ant species records are reported for the Hawaiian Islands. Specimens for both species were first collected in the spring of 2000 by K-12 students and classes as part of an ongoing survey for the little fire ant, Wasmannia auropunctata (Roger), on Hawai‘i Island. Discovery of the little fire ant on Hawai‘i and Kaua‘i (Conant & Hirayama, 2000) elicited survey and control activities by the Hawaii Department of Agriculture (HDOA) and stimulated the creation of a traveling educational curriculum through the University of Hawai‘i. Intermediate and high school students collected ants from their backyard environment with the goal of finding additional infestations of W. auropunctata. One of us (DSG) analyzed and identified all ants in these samples, which contained the two species new to Hawai‘i, and mapped their distributions. Details of this program will be reported elsewhere (D. Gruner, unpubl.). Concurrently, HDOA (RAH. & MEC) discovered one of these ant species during surveys on the island of O‘ahu.
Regressions of length and width to predict arthropod biomass in the Hawaiian Islands
(Pacific Science, 2003) Gruner, Daniel
Biologists in many fields use published regression equations to predict biomass from simple linear body measurements. Power functions are used with arthropods, facilitating biomass estimation of a sample when destructive techniques are not feasible. Resulting predictive coefficients vary widely depending on region and taxa. There are no published biomass regressions for oceanic island fauna, despite the widely accepted conclusion that their arthropod assemblages are unusual in composition. I present a suite of general and taxonomically and morphologically restricted regression equations developed for arthropods in the Hawaiian Islands. General regression equations were highly significant when only length was used to predict biomass, but fits were usually improved by including body width. In regressing restricted sets of taxa, the addition of width did little to improve the fit of the functions. Thus, the choice of regression equations involves a trade-off in taxonomic resolution: precise biomass estimates will come either from (1) low taxonomic resolution measured for both length and width, or (2) high taxonomic resolution measured only for body length. These equations have a high predictive capacity for a broad range of arthropod taxa common in the Hawaiian Islands and, in the absence of locally developed equations, the arthropods of other oceanic islands.
STUDIES ON THE PHYLOGENETIC RELATIONSHIPS OF THE SUPERFAMILY OPOMYZOIDEA WITH AN ASSESSMENT OF THE PHYLOGENETIC UTILITY OF THE INTERNAL FEMALE REPRODUCTIVE TRACT AND A GENERIC REVISION OF AULACIGASTER MACQUART (DIPTERA, CYCLORRHAPHA).
(2003-12-19) Chaves, Alessandra; Charles , Mitter; Mathis, Wayne N.; Shultz, Jeffrey; Delwiche, Charles; Entomology
This work is directed at defining and elucidating some of the basic problems in the phylogenetic classification of the Opomyzoidea. (chapter 1). In chapter 2, I present a quantitative phylogenetic analysis of the Asteioinea (Opomyzoidea). The ingroup and outgroup samples accommodate differing hypothesis of relationships by authors since Hennig. A total of 49 exemplar species and 123 morphological characters are analyzed under six combinations of character coding and weighting methods. The results support the monophyly of the Opomyzoidea and Asteioinea sensu J. F. McAlpine (1989), with the exception that the Odiniidae is separated from the Opomyzoidea by several outgroup nodes. The outgroup consistently nearest the Opomyzoidea is the family Chyromyidae (Sphaeroceroidea). Within Asteioinea, Asteidae + Xenasteidae are consistently grouped with Aulacigastridae, and Neminidae + Neurochaetidae + Periscelididae are consistently grouped together. The position of the Teratomyzidae is uncertain. The genera Stenomicra, Cyamops and Planinasus consistently grouped with the Periscelididae. The sister-group of Aulacigaster is an undescribed genus from Malaysia, and I propose to expand the definition of the Aulacigastridae to include that taxon. In chapter 3, I revise the World species of the genus Aulacigaster Macquart, now numbering 42. New species are described for the Neotropical (28 spp) and Oriental (1 sp) regions, and the genus is divided into six species groups, of which five are new. Keys to species, diagnoses, detailed distributional data, notes on the biology and illustrations are provided to assist species identification. Based on a quantitative phylogenetic analysis, I provide evidence for the monophyly of the Aulacigaster, and the included species groups In chapter 4, I describe the internal female reproductive tract of six species of Opomyzidae, representing three of the four known genera of the family, which I compare with the female tract of other opomyzoid families. The following structures of the female genital tract may prove informative within the context of phylogenetic analyses of the Opomyzoidea: the presence/ absence of multiple chambers in the ventral receptacle; the degree of sclerotization and shape of the ventral receptacle; and the presence of a ring-shaped sclerotization on the wall of the vagina, posterior to the ventral receptacle.
Evaluation of Conservation Strips as a Conservation Biological Control Technique on Golf Courses
(2003-12-22) Frank, Steven; Shrewsbury, Paula M; Entomology
Conservation strips combine the conservation biological control tactics of beetle banks and flowering insectary strips. Conservation strips were established on golf course fairways to evaluate their effect on arthropod abundance and distribution. The conservation strips contained two flowering plants, alyssum and coreopsis, and an ornamental grass. In general, the plants species in the conservation strips supported a greater abundance of predators, parasitoids and alternative prey than turf. Conservation strips also resulted in a greater abundance of natural enemies and alternative prey in the fairway adjacent to the conservation strips versus fairways without conservation strips. Predation on cutworm larvae in fairways was significantly more frequent when conservation strips were present. For these reasons conservation strips show great potential as a conservation biological control tactic on golf courses. Installation of conservation strips could result in reduced pest pressure and a reduction in the need for insecticide applications on golf courses.
Arthropods from ‘ōhi‘a lehua (Myrtaceae: Metrosideros polymorpha), with new records for the Hawaiian Islands
(Bishop Museum Occasional Papers, 2004) Gruner, Daniel
This paper presents new records, range extensions, and a checklist of arthropod species found associated with the most common and widespread native tree in the Hawaiian Islands, ‘öhi‘a lehua (Myrtaceae: Metrosideros polymorpha Gaudichaud-Beaupré). Metrosideros polymorpha is found on all the main islands, naturally occurs from sea level to tree line (>2000 m), in dry, mesic, and wet forests, and is the canopy dominant in old growth and the first woody colonist on recent basaltic lava flows (Dawson & Stemmerman, 1990). Numerous insect species use ‘öhi‘a lehua as a resource for either food or habitat space, and it may have the largest fauna of any native plant (Southwood, 1960; Stein, 1983). Metrosideros is an important, year-round nectar resource for native bees, moths, thrips and other insects, and for native nectarivorous birds, such as the ‘apapane (Himatione sanguinea), ‘i‘iwi (Vestiara coccinea), and ‘akohekohe (Palmeria dolei). Metrosideros also provides important habitat for birds that forage for arthropod prey in the foliage (e.g., ‘akepa [Loxops coccineus]) and bark (e.g., Hawai‘i creeper [Oreomystis mana]). It can be argued that M. polymorpha is the backbone of Hawaiian forests and one of the most important resources for the long-term stability of ecosystems and watersheds in the islands.
Attenuation of top-down and bottom-up forces in a complex terrestrial community
(Ecology, 2004) Gruner, Daniel
Carnivore (top-down) and resource (bottom-up) influences in food webs are strong and pervasive, but few studies have investigated their interactive effects in species-rich terrestrial ecosystems. This study focused on arthropods associated with the dominant tree species, Metrosideros polymorpha (Myrtaceae), in Hawaiian forests. Severe soil nutrient limitation on a 120-yr-old lava flow was removed by fertilization and combined with bird predator exclusion cages in a randomized block design. Arthropod densities were measured from clipped foliage at the outset and conclusion of a 33-mo experiment, and their biomass was estimated using regression equations. Metrosideros foliar nitrogen, tree growth, and biomass increased directly in response to fertilization but did not change with bird exclusion. Fertilization increased detritivore densities but not biomass, and both density and biomass of herbivores, while bird exclusion increased both density and biomass of carnivores. Fertilization also increased spider density and biomass, but bird exclusion increased spider numbers (15 species) only in high resource plots. Overall, trophic level biomass responses were less pronounced than density because smaller bodied individuals responded more to enrichment. Bottom-up factors controlled basal trophic levels, and detritivores comprised the largest fraction of arthropod density and biomass. Conversely, top-down impacts were apparent but variable, limited to higher order consumers, and did not cascade to the level of primary producers. These experimental results were consistent with the view that complex forest ecosystems are structured on a bottom-up template.
THE INFLUENCE OF THERMAL ENVIRONMENT ON DEVELOPMENT AND VULNERABILITY TO PREDATION OF THE AZALEA LACE BUG, STEPHANITIS PYRIOIDES (HETEROPTERA: TINGIDAE)
(2004-01-09) Lepping, Miles; Shrewsbury, Paula M; Raupp, Mike J; Denno, Robert F; Entomology
Differential thermal environments were examined for their influence on performance traits of a key ornamental pest, the azalea lace bug, Stephanitis pyrioides, in the presence and absence of a generalist predator, the green lacewing, Chrysoperla carnea. In laboratory studies, duration of development increased for nymphal instars of S. pyrioides as temperature decreased, producing significant developmental lags in cooler environments. Predation trials identified early nymphal stages as more susceptible to predation than older, dispersal-capable stages, specifically in warmer environments. Additionally, morphological characteristics attained at adulthood combined with behavioral defenses may mediate the reduction in consumption of later S. pyrioides stages by piercing-sucking arthropods such as C. carnea. Field studies confirmed development and life-stage vulnerability findings from the laboratory, however, differential thermal environments created by shading did not generally influence predation. In urban landscapes, S. pyrioides may attain a degree of enemy-free space by occupying a thermal refuge in sunny, exposed habitats.
NUTRIENT AND STRUCTURAL EFFECTS OF DETRITUS ON FOOD WEB INTERACTIONS IN AN INTERTIDAL MARSH
(2004-05-05) Hines, Jessica; Denno, Robert F; Entomology
In most systems the majority of plant primary production is not directly consumed by herbivores, but instead dies and enters the system as detritus. This study examines indirect (nutrient) and direct (structural) impacts of detritus on the aboveground community of arthropods associated with the Spartina alterniflora. I manipulated carbon, nitrogen, and detrital resources in a field experiment and measured the response of the aboveground and belowground communities. Herbivore density in the field was limited by carbon supplements that also decreased decomposition rates, and limited plant size as well as predator abundance. Nitrogen addition enhanced herbivore density by increasing decomposition rate, inorganic soil nitrogen pools, and plant quality. In the laboratory, thatch directly affected herbivore fitness by decreasing survivorship and male body size. Overall, results suggest that detritus has the potential to adversely affect aboveground herbivores directly by decreasing fitness and indirectly by reducing plant biomass and enhancing natural enemy abundance.
Revision of the Genera of the Rhagionidae of the World (Diptera: Brachycera)
(2004-06-08) Kerr, Peter H.; Mitter, Charles; Woodley, Norman E.; Entomology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
As a group, flies represent one of the most prolific and important elements of our natural world. The order Diptera comprises approximately 150,000 species in approximately 142 families. My research focuses on the Rhagionidae (formerly known as the Leptidae), a family of flies considered to contain some of the most primitive living members of the dipteran suborder Brachycera and believed to have diversified as early as 170 million years ago. The taxonomic classification of the Rhagionidae has been unstable for decades because there are few morphological characters that can be used to support hypotheses of relationship among its members. Much of the morphology in this group, however, has not been examined systematically. An independent estimate of phylogeny for the group is carried out and presented here, based on 208 morphological characters for 43 ingroup species and molecular characters consisting of 3200+ bp sequences of 28S rDNA of 34 ingroup species. The goal of this work is to better understand how the genera of the Rhagionidae relate to one another and to their kin within the infraorder Tabanomorpha. Ultimately, this knowledge is fundamental for developing a stable classification system for the group. The Rhagionidae are recognized as a monophyletic group containing four subfamilies containing a total of 17 extant genera. The subfamily Spaniinae is defined by a special modification of tergite 9 of the female genitalia, which is shared by members of Omphalophora, Ptiolina, Spania, Spaniopsis, and Symphoromyia. Omphalophora Becker is resurrected from synonymy with Ptiolina. Spaniinae is defined by having scale-like thoracic hairs, as in Chrysopilus, Schizella and Stylospania. Arthroceratinae contains a single enigmatic genus, Arthroceras. Most females belonging to these three subfamilies have spermathecal duct accessory glands. These structures are reported here for the first time and are unique in Tabanomorpha. The Rhagioninae is the most primitive subfamily of the Rhagionidae. The saw sclerite in the larval mandible may be synapomorphic for this subfamily. Members of Rhagioninae include Atherimorpha, Desmomyia, Rhagio, and Sierramyia gen nov. Rhagina Malloch is recognized as a junior synonym of Rhagio. The Bolbomyiidae are recognized at the family level for the first time. Alloleptis tersus is incertae sedis within Tabanomorpha. Two new species are described: Schizella woodleyi (from Luzón, Philippines) and Sierramyia chiapasensis (from Chiapas, Mexico). A key is given to the genera of the Rhagionidae with dichotomies leading to all families of Tabanomorpha. Genera of Austroleptidae, Bolbomyiidae, and Rhagionidae are diagnosed and described, with a list of included species for each genus.