Adult Diptera Research Articles

Vertical location of ephemeral resources by adult Diptera: Implications for the colonization of cadavers in high-rise buildings

Sarcosaprophagous flies (Diptera) rank among the most common insects associated with human-transformed environments all over the world. Synanthropic species of the families Calliphoridae, Muscidae, Sarcophagidae and Phoridae, in particular, have tremendous forensic importance due to their ability to colonize human cadavers and thus provide information on minimum post-mortem interval. Recently, cases of flies colonizing cadavers inside buildings of different heights drew attention to the vertical dispersal abilities of these flies, a subject that has received little attention. We investigated the vertical distribution of sarcosaprophagous flies in an urban environment, using uninhabited buildings as experimental models in Northeastern Brazil. To assess the vertical stratification of flies, one in every three floors of nine buildings was sampled using traps baited with bovine spleen, from the ground to the 27th floor. Calliphoridae was the most abundant family (52.9%), followed by Muscidae (41.2%), Sarcophagidae (3.2%) and Phoridae (2.7%). Most of the insects were collected at ground level (78.8%), with a decreasing abundance registered on the higher floors. Nevertheless, adults of the four families tested here were able to reach substrates as high as the 15th floor, which corresponds to approximately 48 m in height. Regarding calliphorids, seven species were identified, of which Chrysomya albiceps (30.4%) and C. megacephala (68.3%) were the most abundant. This is, to our knowledge, the first detailed, replicated study on vertical resource localization of sarcosaprophagous flies.

Temporal segregations in the surface community of an ephemeral habitat: Time separates the potential competitors of coprophilous Diptera

AbstractTemporal separations among species greatly enhance the species' coexistence, especially in insect communities inhabiting temporally unstable, yet resource‐rich, ephemeral habitats like dung or carrion. The insect communities inhabiting ephemeral habitats consist of two components, the internal community dwelling within the substrate (mostly Coleoptera), and the surface community inhabiting the habitat's outer rim (mostly adult Diptera). In contrast to the internal community, the surface community is very rarely studied. We present here the first quantitative study of temporal trends in the surface community of coprophilous dipteran adults. Using artificially created 1.5 L cow dung pats, we studied the succession and seasonality in the surface community during six sampling periods in 2011 and 2012. In total, we sampled 13579 adults of dung‐visiting Diptera. Both the abundance and species richness decreased rapidly throughout the succession, and were highest during summer. Along the successional gradient, the community was separated into two main groups (early and late) and four subgroups: (i) species occurring during the first few hours (mainly Calyptratae: Diptera); (ii) species occurring between the first and second days; (iii) species occurring between the second and third days (mainly Acalyptratae: Diptera); and (iv) species with optima after the third day of dung pat existence (mainly Nematocera). The earliest and latest successional groups, occurring mainly during spring–autumn, were seasonally separated from the two mid‐successional groups, occurring during summer. The ecologically similar species displayed detectable seasonal micro‐optima, which likely facilitate their coexistence. There was a high overall similarity in temporal patterns between dung and carrion surface communities.

Seasonal, Locality, and Habitat Variation in Assemblages of Carrion-Associated Diptera in Gauteng Province, South Africa

Seasonal, spatial, and habitat responses of carrion-associated Diptera assemblages can provide valuable information about the presence or absence of species and their relative abundance, and thereby enhance understanding of their responses to environmental variables and how this may have an impact on forensic investigations. Three different nature reserves (localities) within the Municipality of Tshwane, South Africa, were selected to determine whether species assemblages of carrion-feeding flies differ between seasons, localities, and habitat types. A total of 59,511 adult Diptera, identified to 35 species in eight different families, were collected using modified Redtop hanging traps, baited with liver and fish, during four seasons in three different habitat types. Species assemblages differed temporally, with season being the main factor determining species diversity and not locality or habitat. However, savanna and human-disturbed habitats supported a higher abundance and species richness than grassland habitats. Areas adjacent to the localities, such as large urban expanses in Dinokeng or agricultural holdings in Rietvlei, led to an increase in the abundance and mean species richness of carrion-associated Diptera, and in increased numbers of pest or invasive species such as Chrysomya megacephala (F.). Despite this, the overall species assemblages present in human-disturbed areas were very similar to those recorded in natural habitats.

POSTMETAMORPHIC GROWTH IN LIPOPTENA CAPREOLI RONBANI (HIPPOBOSCIDAE) AND OTHER INSECTS

ABSTRACT A process of growth was found to take place in adult Diptera, Hymenoptera and Coleoptera examined. The process consists of growth of apodemes, thickening of the cuticle, thickening of muscles and displacement of fibers. Formation of new muscle fibers was observed in Lipoptena. The process is not uniform in different groups of insects, and in some eases one or more of the processes mentioned were absent.

Spatial and temporal dynamics of invertebrates dwelling karstic mesovoid shallow substratum of Sivec National Nature Reserve (Slovakia), with emphasis on Coleoptera

AbstractInterior spaces of the forested rocky debris (MSS) represent a transition zone between the surface and deep underground spaces and a place of animal adaptation to underground life. They serve as a refuge for relict fauna as well. The study was conducted in the limestone scree slopes in Sivec National Nature Reserve (Čierna Hora Mts, Western Carpathians, elevation about 500 m a. s. l.) covered by linden-maple forest from September 2008 to November 2009. The effort was to define the vertical and seasonal aspects of invertebrates and temperature regime. Invertebrates were collected by using subterranean traps (plastic cups with 4% formaldehyde, inserted into the depths 5–95 cm through a plastic tube), which were checked monthly. Almost 26,000 specimens were trapped. Arthropods highly dominated over gastropods and earthworms. Collembola (67.61%) and Acarina (15.55%) were eudominant. Macrofauna was represented mainly by larvae of Holometabola (7.55%) and adult Diptera (5.11%) and Coleoptera (1.13%). All these groups were captured along the total depth gradient. Coleoptera were studied in more details. Among 11 Coleoptera families, Staphylinidae predominated and were captured at all levels. Rather high species diversity was found: 67 spp. excluding common epigeic fauna. Some species supposed to be subterranean, e.g., Bryaxis frivaldszkyi slovenicus, Duvalius bokori valyianus and Omalium validum. Activity of most invertebrate groups decreased significantly with depth (prevalence of surface fauna), but it was not terminated at 1 m under surface; the same was true for beetles, both in activity and diversity. Conspicuous fact is that a mass of subterranean species were traced also close to the surface (35 cm), i.e., probably it is not necessary to put the traps as deep as in this study. Seasonal climate changes affected the activity of invertebrates which was the highest at the end of spring and the lowest during winter, but it was not completely interrupted. Microclimate was characteristic without major temperature fluctuations on the surface. It was stable deeper along with increasing average annual temperature. High diversity and the occurrence of rare faunistic elements as well as specific habitats of MSS are perspective study objects and they merit care; mature design of the next studies considering the effect of season and depth of traps deposition shall do them more effective and less laborious.

Impact of a reduced winter snowpack on litter arthropod abundance and diversity in a northern hardwood forest ecosystem

Projected changes in climate for the northeastern USA over the next 100 years include a reduction in the depth and duration of the winter snowpack, which could affect soil temperatures and frost regimes. We conducted a snow-removal experiment in a northern hardwood forest at the Hubbard Brook Experimental Forest in central New Hampshire over 2 years to induce soil freezing and evaluate its effect on the abundance, richness, and diversity of soil arthropods during the growing season. Snow removal at the beginning of winter increased the depth and duration of soil frost, decreased soil temperatures, and led to a reduced abundance of some arthropod taxa, including Araneae (reduced by 57%; P=0.0001), Pseudoscorpionida (75%; P<0.0001), Hymenoptera (57%; P=0.0033), Collembola (24%; P=0.0019), adult Coleoptera (23%; P=0.0057), and larval Diptera (33%; P<0.0001) and an increase in other taxa, including Hemiptera (increased by 7%; P=0.032). Taxa that did not respond significantly to snow removal included Chilopoda (P=0.55), Acari (P=0.66), Diplopoda (P=0.66), adult Diptera (P=0.54), and larval Coleoptera (P=0.39). A delayed snowpack over two winters also resulted in decreased arthropod richness by 30% (P<0.0001) and Simpson's index of diversity by 22% (P=0.0002) during the two subsequent growing seasons. Results of this study demonstrate that predicted changes in the winter snowpack and depth and duration of soil frost may reduce the abundance and alter the community composition of arthropods living in the forest floor of northern hardwood forests, which could have implications for the structure and function of northern forest ecosystems.

Universal primers for rapid detection of hytrosaviruses

Hytrosaviridae is a proposed virus family encompassing viruses that cause salivary gland hypertrophy (SGH) syndrome in infected insects and reduce the fertility in their dipteran insect hosts. They contain a large, double stranded DNA genome of 120–190 kbp. To date, these viruses have been detected only in adult Diptera. These include hytrosaviruses detected in various tsetse fly species ( Glossina spp.), the narcissus bulb fly Merodon equestris and the house fly Musca domestica. The limited number of hytrosaviruses reported to date may be a reflection of the frequent absence of external symptoms in infected adult flies and the fact that the virus does not cause rapid mortality. Based on the complete genome sequence of Glossinia pallidipes (GpSGHV) and Musca domestica (MdSGHV) salivary gland hypertrophy viruses, a PCR based methodology was developed to detect the viruses in these species. To be able to detect hytrosaviruses in other Diptera, five degenerate primer pairs were designed and tested on GpSGHV and MdSGHV DNA using gradient PCR with annealing temperatures from 37 to 61 °C. Two pairs of primers were selected from p74, two pairs from PIF-1 and one pair from ODV-e66 homologous proteins. Four primer pairs generated a virus specific PCR product on both MdSGHV and GpSGHV at all tested annealing temperatures, while the ODV-e66 based primers did not generate a virus specific product with annealing temperatures higher that 47 °C. No non-specific PCR product was found when using genomic DNA of infected flies as template DNA. These results offer new sets of primers that could be used to detect hytrosaviruses in other insects.

Adult Diptera from Ozark Caves

The Diptera fauna of Ozark caves is fairly typical of that found elsewhere in the United States east of the Great Plains. The sphaerocerid Spelobia tenebrarum is the only troglobitic dipteran found in Ozark caves. Probable troglophiles include the mycetophilid Macrocera nobilis, the psychodids Psychoda spp., and the phorid Megaselia cavernicola. The tipulids commonly found in Ozark caves, such as Dactylolabis montana, Dolichopeza spp. and Limonia spp. are probably all trogloxenes, as are the Trichoceridae and Heleomyzidae. The mycetophilids, Exechiopsis umbratica and Rymosia sp., and the culicids are among the most common cave dipterans in the study area. The culicids overwinter in caves and other protected places; they are properly classified as trogloxenes. The main sources of food for cave Diptera are other insects, carrion, guano, and allochthanous plant debris.

Succession pattern of cadaverous entomofauna in a semi-rural area of Bogotá, Colombia

The main objective of this work was to examine the succession of insects colonizing three pig ( Sus scrofa) cadavers in a semi-rural area of Bogotá. The 12 kg pigs were shot and put into metallic mesh cages to allow access by insects. Arthropods were then sampled at different intervals depending on the corresponding stage of decomposition. In total 5981 arthropods were collected during decomposition, 3382 adults and 2599 immature stages, belonging to 10 orders and 27 families. Sarconesia magellanica and Compsomyiops verena (Diptera: Calliphoridae) were the first species to colonize the corpses. Egg masses and 1st stage Calliphoridae larvae were associated with the fresh stage of decomposition, 1st and 2nd stage larvae of Calliphoridae and Sarcophagidae during chromatic and emphysematous stages, immature Chrysomya albiceps (Diptera: Calliphoridae), Ophyra sp. (Diptera: Muscidae) and Oxellytrum discicolle (Coleoptera: Silphidae) during the colliquative stage and mainly Coleoptera during the skeletization phase (plus some adult Diptera). The data obtained in the present investigation could be used for the estimation of postmortem interval (PMI) in real cases when the conditions to which a cadaver has been exposed are similar to those recorded during this work.

Diet and morphology through ontogeny of the nonindigenous Mayan cichlid ?Cichlasoma (Nandopsis)? urophthalmus (G�nther 1862) in southern Florida

We evaluated diet and morphology through ontogeny for a freshwater population of the Mayan cichlid ‘Cichlasoma (Nandopsis)’ urophthalmus (Gunther 1862) in Florida’s Big Cypress National Preserve. This species is a generalist predator throughout ontogeny. Fish remained the primary prey item throughout ontogeny, but there was a shift from detritus and ostracods among juveniles to algae, gastropods (snails), decapods, Hymenoptera, and adult Diptera among adults. All morphological variables grew isometrically except total molariform tooth area and pharyngeal jaw mass, which exhibited positive allometry. Despite a moderately robust adult pharyngeal jaw apparatus, this species does not specialize on hard prey at this south Florida site. Compared to its native range in Mexico, fish in Florida have undergone a pronounced niche shift with the diet being dominated by fish and snails, probably due to greater availability. The invasive success of C. urophthalmus does not appear to be related to ontogenetic morphological shifts or dietary specialization. Rather, its successful and rapid colonization of southern Florida might in part be related to its generalized and opportunistic feeding habits and morphology.

Biological and chemical assays of pyrethroids in cattle dung.

Bioassays were developed in Zimbabwe to measure pyrethroid in cattle dung. These and chemical assays then estimated concentrations in dung from treated oxen and elucidated risks to dung fauna. Laboratory bioassays with adult beetles (Histeridae and Scarabaeinae, including Copris, Digitonthophagus, Onitis and Sisyphus spp.) and muscoid larvae (Musca lusoria Wiedemann) indicated that the LC50 of pyrethroids, as ppm in the wet weight, averaged 0.04 for deltamethrin pour-on, 0.25 for deltamethrin dip, 0.22 for alphacypermthrin pour-on, 0.10 for cyfluthrin pour-on, 0.23 for cypermethrin dip and 0.63 for flumethrin dip. Field bioassays involved artificial dung pats of 800 g, deployed in woodland and inspected after 24 h to record insects dead and alive. Beetles were most abundant in the wet season. Muscoid larvae were less seasonal. The LC50 of insecticides in the field confirmed laboratory indications. Adult Diptera (muscoids and Sgifidae) were not repelled or killed until the deltamethrin concentration reached 10 ppm. Pat dispersal by dung fauna and termites (Microtermes spp.) was halved by deltamethrin at 0.1-1 ppm. Scavenging of dead beetles by ants was greatest with small beetles (< 15 mm long) uncontaminated with insecticide. Dips and pour-ons of deltamethrin on cattle gave residues of about 0.01-0.1 ppm in dung produced in the fortnight after application. About 1.6% of the deltamethrin applied was transferred to dung. Deltamethrin and alphacypermethrin in dung showed no detectable degradation in 64 days. Contamination levels threaten populations of slow-breeding beetles.

COMPARATIVE NESTING BEHAVIOR OF CRABRO MONTICOLA (HYMENOPTERA: SPHECIDAE)

The nesting behavior of Crabro monticola was studied at seven localities in upstate New York and northwestern Pennsylvania over seven years. More than 100 nests were observed, excavated, measured, and drawn. Contents were removed from the cells, analyzed, weighed, and identified. All nests were excavated in sandy soil near woodland in late spring-early summer. Prey were carried to the nests in flight mainly during the morning and, less so, late afternoon. A total of 11 families and 61 species of adult Diptera were preyed upon. Males of Hybomitra lasiophthalma (Tabanidae) were predominant prey at S Auburn, NY. Males of Thereva frontalis (Therevidae) were prevalent in cells at Chittenango and Colonie, NY. Individual burrows varied in length, but mean burrow length was similar at all localities except Selkirk Shores State Park and Colonie, NY. Mean cell depth was significantly different between most sites. Prey stored for next generation male wasps weighed, on average, only half as much as provisions stored for future female wasps. Female cells were located, on average, slightly deeper in the soil than male cells except at Chittenango in 1970. Individual flies varied considerably in size and weight at all localities. Mean number of prey per cell at S Auburn was significantly fewer than at Chittenango. Cell size correlated positively with aggregate prey weight. Flies bearing wasps' eggs were nearly always positioned head in and ventral side up. Mortality by mold, scavenging ants, and cleptoparasitic miltogrammine flies was negligible.

Influence of management type on Diptera communities of coniferous plantations and deciduous woodlands

The contribution of four types of secondary woodlands to Scottish invertebrate biodiversity was investigated for coniferous plantation forestry, riparian ash–alder woodlands, early successional deciduous woodlands and climax deciduous woodlands. Considerable variation in the type and intensity of management within these four woodland types existed. Adult Diptera from 21 families, representing diverse trophic and ecological guilds, were sampled from 31 woodlands in the Aberdeenshire region of northeast Scotland, between June and August 2001. Environmental differences between woodlands were recorded at each site using environmental parameters such as pH and organic matter content, vegetation characteristics, including percentage canopy cover and dominant field layer plant species. Multivariate ordination techniques detected significant responses in the Dipteran communities to soil type, organic matter content, soil pH, field layer plant species richness, dominant field layer plant species and percentage cover of Pteridium aquilinum. Responses in terms of Dipteran abundance, species richness, diversity and evenness were observed to soil type and dominant species of the field layer vegetation. The role of woodland type and management in diversifying Diptera communities is discussed with a view to maintain and possibly enhance Dipteran and other invertebrate communities in Scottish secondary woodlands.

Elevated numbers of flying insects and insectivorous birds in riparian buffer strips

We compared the abundances of flying insects along undisturbed lakeshores and riparian buffer strips in balsam fir (Abies balsamea) forests in western Newfoundland. Insects were collected in pan traps placed on the forest floor and tanglefoot (sticky) traps suspended within the live canopy. Significantly greater numbers of insects were captured in riparian buffer strips than in undisturbed shorelines for four of five size classes in the canopy and two of five size classes in the understory. Collections were dominated by adult Diptera and Hymenoptera. Mean capture rates along buffer strips were 120-200% of the mean capture rates along undisturbed shorelines. This increase was greatest for large-bodied insects. A likely explanation for our observations is that buffer strips act as windbreaks, collecting airborne insects blown in from adjacent clearcuts and lakes. This phenomenon has been widely documented in agricultural landscapes. Understory wind speed was generally greater along buffer strips than controls, which is a reflection of increased exposure caused by clear-cutting. A concurrent parallel study conducted at the same sites investigated the effects of riparian buffering on breeding bird assemblages. Ubiquitous insectivorous birds, including the yellow-rumped warbler (Dendroica coronata) and blackpoll warbler (Dendroica striata), were more abundant along buffer strips than undisturbed shorelines, possibly in response to increased prey availability. Increased food availability may in part explain the high numbers of insectivorous birds typically observed in riparian buffer strips in boreal forests.

Impact of Forest Management on Insect Abundance and Damage in a Lowland Tropical Forest in Southern Cameroon

The rate of deforestation in West Africa was around 2% (12 000 km 2 ) per annum during the 1980s, and recent evidence from Cameroon suggests that the rate of deforestation there has increased during the 1990s. In contrast, only 360 km 2 of plantation forests were established annually during the mid-1980s in West African countries. Recent research in the Mbalmayo Forest Reserve in southern Cameroon has examined contrasting silvicultural techniques for regenerating degraded forest with West African tree species such as Terminalia ivorensis. These techniques included complete clearance, where all existing trees were felled and these and all other vegetation removed from the plots; and partial clearance methods (partial manual clearance, partial mechanical clearance and line planting), where tree-felling resulted in a reduction of 50% of the canopy cover. This paper describes a study of the impact of these techniques on arthropod abundance and the damage caused to T. ivorensis by insect pests within the Mbalmayo Forest Reserve. The amount of damage caused by leaf-mining insects, the abundance of gall-forming mites, and the number of trees affected by shoot borers were not affected by silvicultural practice. The amount of damage caused by leaf-chewing insects was greater in the line planting plots than the complete clearance plots, but the leaf area removed by insects rarely exceeded 6%. It is concluded that the degree of forest clearance before establishing plantations of T. ivorensis. does not markedly affect the amount of damage caused by arthropod pests at the spatial scale at which this study was carried out. Arthropod abundance was assessed by insecticide knockdown fogging in two study sites within the Mbalmayo Forest Reserve. A mean total of 196 arthropods m -2 was recorded, ants being the most common arthropod group (63%), followed by adult Diptera (10%) and then Hymenoptera other than ants (4%), Homoptera (4%), Thysanoptera (4%), adult Coleoptera (3%) and other groups (13%). Ants, Diptera, Araneae, Thysanoptera, Homoptera, Coleoptera and Orthoptera were significantly more abundant in the partial manual clearance plot than the complete clearance plot in one or both of the study sites. Because several of these groups are composed mainly of predatory and parasitic species, it is possible that, despite the pest damage results summarized above, the long-term likelihood of pest outbreaks occurring on T. ivorensis is lower in partial clearance than complete clearance plantations. However, our current lack of knowledge of the species composition of different arthropod groups limits the relevance of these findings.

The ecdysoid RH5849 induces yolk polypeptide synthesis in male flies

Summary RH5849 is a benzoyl hydrazine analog which has been reported to mimic several effects of the arthropod steroid hormone ecdysone to which it is chemically totally unrelated. In adult Diptera, ecdysone is the hormone that triggers vitellogenin synthesis. We report here that RH5849, upon oral ingestion, is able to induce vitellogenin synthesis in male Drosophila, Neobellieria, Phormia and Lucilia. This contrasts to data in the literature which showed that RH5849 could not mimic the pupariation-inducing effect of ecdysone in last instar fly larvae. RH5849 neither exerts a juvenile hormone mimicking effect nor behaves as an anti-juvenile hormone in both the Colorado potato beetle and Galleria.

Effect of sewage effluent on soil fauna in a Pinus-radiata plantation

Water and nutrients in effluent applied to land may influence soil processes. This study uses late summer and autumn samples to assess changes in litter and soil fauna under a 17-year-old Pinus radiata plantation on dune sands of the Waitarere-Hokio association after 7 years of spray irrigation of sewage effluent. Populations estimated included 12 groups of litter arthoropods, earthworms, enchytraeids, tardigrades, rotifers and nematodes. Three groups of litter arthropods (adult diptera, spiders and aphids) were significantly less abundant in the effluent-treated area than in the unirrigated control. Increased moisture content was apparently responsible for greatly increased populations of earthworms and nematodes in the effluent-treated area. Bacterial-feeding and predatory nematodes showed marked increases, while fungal-feeding nematodes declined significantly. The nematode maturity index (MI) was lower in all treated plots. After effluent had been withheld for 52 days, there were significant increases in isopods and Collembola. Rotifers were most abundant in the control area. It appears that effluent enhanced physical breakdown of the P. radiata litter. Movement of the decayed fragments into the upper layers of sand may have produced conditions unfavourable for enchytraeids and rotifers.

Food interrelationships between brown trout, Salmo trutta L., and rainbow trout, Oncorhynchus mykiss (Walbaum), in a small put-and-take stillwater fishery

. The food of brown trout, Salmo trutta L., and rainbow trout, Oncorhynchus mykiss (Walbaum). in a small stillwater put-and-take fishery in Surrey, England was examined by stomach content analysis of fish caught by angling between the months of April and September 1985. Overall, brown and rainbow trout tended to utilize different food sources. Mann-Whitney U-tests showed most major food items to be eaten in significantly different amounts, the most important exceptions being chironomid pupae and adult Diptera. In all months except April, rainbow trout utilized mainly midwater food, particularly Cladocera. Brown trout fed mainly on benthic food organisms and fish. Spearman rank correlations showed diets to be dissimilar during this period, with significant negative correlations in May and August. These results indicate an absence of interspecific competition for food, and imply spatial separation of brown and rainbow trout. In April both brown and rainbow trout fed extensively on the temporary bottom fauna, mainly trichopteran and megalopteran larvae, and diets were significantly positively correlated.

Ultrastructural and biochemical aspects of digestion in the imagoes of the fly Rhynchosciara americana

AbstractThe midgut of adult Rhynchosciara americana Wiedemann (Diptera: Sciaridae) displays, in contrast to the midguts of other adult Diptera, two caeca connected to a ventriculus. All midgut cells exhibit long apical microvilli, and narrow and ramified basal channels with openings to the underlying space. These morphological features are thought to be involved in the absorption of nutrients from food. Enzymatic assays in R. americana adults revealed that amylase occurs in salivary glands and midgut, whereas aminopeptidase, α‐glucosidases and trypsin occur only in the midgut, mainly in the ventriculus. There is a soluble (Mr 105000) and a membrane‐bound aminopeptidase (solubilized form, Mr 110000). Soluble α‐glucosidase inactivates easily and could not be characterized, whereas membrane‐bound α‐glucosidases were resolved after solubilization into three molecular species (Mr 186000, 105000 and 84000) with different substrate specificities. The activities of trypsin (pH optimum 9.0), which was inhibited completely by soybean trypsin inhibitor, and of amylase (pH optimum 5.5), were not sufficiently high to be further characterized. The data support the assertion that R. americana adults are able, to a limited extent, to digest and absorb starch and proteins, in addition to nectar sugars. The results, supported by published data, suggest that there is an inverse correlation between the digestive enzyme activities and midgut absorptive surface in insects which has nectar as a major food.

ATP‐dependent Ca2+ transport and Ca2+‐ATPase activities in an enriched plasma membrane fraction from gypsy moth larval midgut tissue

AbstractA subcellular fraction enriched in plasma membranes was obtained from gypsy moth (Lymantria dispar) larval midgut tissue. Using [45Ca]2+ as a tracer, Ca2+ transport activity by membrane vesicles in the enriched fraction was measured and shown to be ATP‐dependent, with a very high affinity for Ca2+ (apparent Km for [Ca2+ free]Abbreviations used: [Ca2+free] = concentration of free (unbound) calcium ion;CaM = calmodulin; F = fraction; IOV = inside‐out membrane vesicles; W‐5 = N‐(6‐aminohexyl)‐1‐naphthalenesulfonamide; W‐7 = N‐(6‐aminohexyl)‐5‐chloro‐1‐naphthalenesulfonamide. = 22 nM). Ca2+ transport was abolished upon addition of the calcium ionophore, A23187. Ca2+‐stimulated, Mg2+‐dependent ATPase activity peaked between 100 and 200 nM Ca2+free. Ca2+‐Mg2+‐ATPase activity was inhibited by vanadate, 2 phenothiazine drugs (trifluoperazine and chlorpromazine), and the naphthalene sulfonamide, W‐7; the related compound, W‐5, and ouabain had a negligible effect. These results suggest the presence of a high affinity plasma membrane Ca2+ pump in gypsy moth larval midgut cells and are discussed in light of earlier work involving calcium transport in isolated midguts of larval Hyalophora cecropia. Ionic and other conditions that characterize the midgut physiology of larval Lepidoptera (e.g., luminal pH; electrochemical gradient for Ca2+; effect of certain ions and inhibitors on Ca2+ transport) contrast significantly with those found in adult Diptera. The implications that these differences may have for calcium regulation are discussed. © 1992 Wiley‐Liss, Inc.