Soft-bodied Arthropods Research Articles

Persisting roadblocks in arthropod monitoring using non-destructive metabarcoding from collection media of passive traps.

Broad-scale monitoring of arthropods is often carried out with passive traps (e.g., Malaise traps) that can collect thousands of specimens per sample. The identification of individual specimens requires time and taxonomic expertise, limiting the geographical and temporal scale of research and monitoring studies. DNA metabarcoding of bulk-sample homogenates has been found to be faster, efficient and reliable, but the destruction of samples prevents a posteriori validation of species occurrences and relative abundances. Non-destructive metabarcoding of DNA extracted from collection medium has been applied in a limited number of studies, but further tests of efficiency are required with different trap types and collection media to assess the consistency of the method. We quantified the detection rate of arthropod species when applying non-destructive DNA metabarcoding with a short (127-bp) fragment of mitochondrial COI on two combinations of passive traps and collection media: (1) water with monopropylene glycol (H2O-MPG) used in window-flight traps (WFT, 53 in total); (2) ethanol with monopropylene glycol (EtOH-MPG) used in Malaise traps (MT, 27 in total). We then compared our results with those obtained for the same samples using morphological identification (for WFTs) or destructive metabarcoding of bulk homogenate (for MTs). This comparison was applied as part of a larger study of arthropod species richness in silver fir (Abies alba Mill., 1759) stands across a range of climate-induced tree dieback levels and forest management strategies. Of the 53 H2O-MPG samples from WFTs, 16 produced no metabarcoding results, while the remaining 37 samples yielded 77 arthropod MOTUs in total, of which none matched any of the 343 beetle species morphologically identified from the same traps. Metabarcoding of 26 EtOH-MPG samples from MTs detected more arthropod MOTUs (233) than destructive metabarcoding of homogenate (146 MOTUs, 8 orders), of which 71 were shared MOTUs, though MOTU richness per trap was similar between treatments. While we acknowledge the failure of metabarcoding from WFT-derived collection medium (H2O-MPG), the treatment of EtOH-based Malaise trapping medium remains promising. We conclude however that DNA metabarcoding from collection medium still requires further methodological developments and cannot replace homogenate metabarcoding as an approach for arthropod monitoring. It can be used nonetheless as a complementary treatment when enhancing the detection of soft-bodied arthropods like spiders and Diptera.

Diversity and distribution of predatory stink bugs from India and their role in insect pest management (Hemiptera: Heteroptera: Pentatomidae: Asopinae

Asopinae is the only subfamily among Pentatomidae (Hemiptera: Heteroptera), whose members exhibit predatory feeding habits. They are called predatory stink bugs as they mainly predate on several soft-bodied arthropods. In this study, we compile a consolidated list of the subfamily Asopinae from India, covering 30 species in 17 genera, supplemented with prey information of selected species based on our observations and literature records.

Ecology and Diversity of Aphids: A Review

Plant lices are tiny, soft-bodied arthropod insects which feed on sap of plants. Aphids are another name for these insects. They are members of the Aphidinae subfamily. Aphids fall into 60 genera and have roughly 400 species globally. In India, there are 25 genera with 125 species of aphids, while Uttarakhand (plains to very high altitudes) has 4 genera with 125 species of aphids. There are 65 different types of aphids, with the genus Aphidius having the most species overall. Aphids are greatly harming horticulture fruits and vegetables as well as agricultural crops. Temperature, humidity, and other environmental conditions affect its outbreak. Aphids are tiny, soft-bodied, viviparous, parasitic insects that lack wings and have wax secreting tubes on their abdomens. They can stunt plant growth, create plant galls, spread viral diseases to plants, and deform leaves, buds, and flowers. They have an impact on both plants, such as roses, lilies, and marigolds, as well as fruits and vegetables including mustard, cabbage, peas, potatoes, and beans. The mountainous area lacks data on the variety, ecology, and inventory of aphids. So an effort has been made to review the aphids diversity in India.

Diversity of phytoseiid mite (Acari: Mesostigmata) fauna from Andaman & Nicobar Islands, India

The highly biodiverse group of mesostigmatid mites belonging to the family of Phytoseiidae are globally recognized as potential predators of small soft-bodied arthropods and destructive mite pests owing to their high searching capacity, good adaptability to a wide range of climatic regimes from arctic to tropics, short life cycle (1 week approx.), high multiplication capability (40–60 offspring per female) with high feeding potential. Phytoseiid mites that are commercially exploited as efficient biocontrol agents are regarded as farmers’ friends as they play a pivotal role in managing the pest population below the economic injury level to ensure a safe and sustainable pattern of food production system keeping aside hazardous chemicals. At present, the global scientific communities are deeply involved with this group of mites and due to their higher attention, the number of nominal phytoseiid species has increased from 34 in 1950 to more than 2500 in 2021.

Predation efficiency of the green lacewings Chrysoperla agilis and C. mutata against aphids and mealybugs in sweet pepper.

Chrysoperla species include well-known predators of aphids and other soft-bodied arthropods. As such, they are considered important biological control agents of herbivorous pests in agroecosystems where many of green lacewings species occur. Despite the high number of species of the genus Chrysoperla, only a few have been assessed for the predation efficiency of their larvae against pests infesting plants, and even fewer are currently marketed for use in biocontrol practice. Difficulties in species identification within the Chrysoperla carnea complex species in particular has been related to varying success of commercial C. carnea s.l. releases in the field. In this study, we assessed the ability of two Chrysoperla species, Chrysoperla agilis a member of the carnea cryptic species group, and Chrysoperla mutata of the pudica group to consume aphid and mealybug individuals and suppress their populations in sweet pepper plants. We found that third-instar larvae of both species were able to consume a high number of aphids (approximately 120 nymphs per larva) and mealybugs (approximately 105 nymphs per larva) within 24 h. Furthermore, the release of second-instar larvae of both C. agilis and C. mutata was shown to be remarkably efficient in suppressing the pest populations in long-term greenhouse experiments. Aphid populations were suppressed by approximately 98% and mealybugs by 78% as compared to control plants. Our results highlight the predation efficiency and the biocontrol potential of two widespread Chrysoperla species for their use in pest control.

Monitoring and assessment of resistance to insecticides in the lacewing Chrysoperla carnea (Stephens).

Chrysoperla carnea (Stephens) is a key predator of several soft-bodied arthropods across various cropping ecosystems. Biological control is a prime strategy to reduce the harmful effects of pesticides on environment especially plants and arthropods. Collection of lacewings (Field Populations) was made during 2014 and repeated in 2016 from five different districts composed mainly by row and vegetable crops under conventional cropping system. For these populations, resistance level to four insecticides representing different mode of action was measured using topical treatment of 1st-instar larvae with prepared dilutions of commercial formulation. The highest resistance levels were found for chlorfenapyr (100.86- to 423.78-fold) and indoxacarb (131.28- to 255.05-fold) in populations from all districts, while buprofezin and nitenpyram resistance was low to high and moderate to high, respectively. The levels of resistance to nitenpyram increased from 2014 to 2016 for populations of 3 out of 4 surveyed areas, while the susceptibility to buprofezin remained unchanged. Decrease in resistance levels for chlorfenapyr and indoxacarb in 2years was marginal. These results suggest that field populations of C. carnea maintained resistance to buprofezin, chlorfenapyr, indoxacarb, and nitenpyram. Current outcomes support the fact that this bio-control agent could be a main nominee for mass release under judicious application of selective insecticides.

Lethal and sublethal effects of lufenuron on the predator Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae)

The neuropteran Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) is a generalist predator present in Mediterranean agroecosystems. It has a wide range of prey including almost all soft-bodied arthropods; its voracity makes it a suitable agent for inclusion in Integrated Pest Management (IPM) programmes. Use of insecticides that inhibit chitin synthesis has increased and includes the use of benzoylureas (e.g. lufenuron) which negatively affect development of the immature stages of phytophagous insects, both by ingestion and by contact. This study evaluated interactions between lufenuron and the predator C. carnea in the laboratory. Treatment of eggs with lufenuron 24 or 48 h after oviposition had no effect on the proportion successfully hatching, or in the survival of resulting neonate larvae. Topical application of lufenuron to second instar larvae (L2) of C. carnea resulted in high mortality rates; lethal concentration to kill 50% (LC50) was 0.0153 ml/L (0.00860–0.0236 ml/L). Moreover, the development time of third-instar larvae of C. carnea that had consumed prey treated with lufenuron 24 h previously (at a dose of 1 ml/L) was significantly truncated and high percentage mortality was observed when these larvae reached the pupal stage. In choice bioassays a high percentage of C. carnea larvae chose prey treated with lufenuron in preference to untreated prey. Ingestion of lufenuron by C. carnea adults had no effect on female fecundity or adult longevity, but caused a significant reduction in the viability of resulting eggs. In light of these results, the developmental stage of C. carnea should be considered when deciding on the timing of lufenuron applications within IPM strategies.

Straight-jawed lacewing larvae (Neuroptera) from Lower Cretaceous Spanish amber, with an account on the known amber diversity of neuropterid immatures

Three larval neuropterans (Insecta: Neuropterida) with straight mandibulomaxillary stylets are described from Lower Cretaceous (late Albian, ~105 Ma) Spanish amber: a third-instar beaded lacewing (Berothidae) from the Peñacerrada I locality (Burgos, Spain), and two specimens from the San Just locality (Teruel, Spain), i.e., a tentative first-instar beaded lacewing and a remarkable specimen considered a berothid-like mantispoid or dilaroid (instar unknown) displaying a combination of potentially plesiomorphic characters and some unique features. These morphotypes are among the oldest straight-jawed neuropteran larvae described. According to the morphology of the specimens and the taphonomy of the amber pieces where they are embedded, the described forms are regarded as active predators of small soft-bodied arthropods, probably living among bark or other vegetation of the resin-producing forest although they could have frequented the soil. An account of the diversity of larval Neuropterida described and/or figured from amber localities worldwide is provided, including reassessments of some specimens. The gathering diversity of fossil immature neuropterans, like that of their adult counterparts, already leans towards reflecting a greater diversity and disparity of the group in deep time ‒particularly during the Cretaceous‒ than in modern days, and it is worthy of increased research efforts due to the evolutionary and palaeobiological potential that it holds.

Immature stages of Blepharotes (Diptera: Asilidae), one of the world's largest assassin flies: multi‐function mandibles and soil‐drilling pupal spines and spurs

AbstractAssassin or robber flies belong to the family Asilidae, one of the most diverse fly families, with over 7400 described species worldwide. Adults are predators on mostly smaller insects which they catch on the wing; larvae are predators on soft bodied arthropods in the soil or rotting wood, usually beetle (Coleoptera) larvae, often curl or white grubs (Scarabaeidae). Predation by larval and adult Asilidae puts downward pressure on populations of their prey above and below ground. Because asilid larvae are cryptic, the immature stages of few species have been described, thus hampering our ability to identify larvae. We describe and illustrate the late instar larva and pupa of one of Australia's largest and most impressive asilid species, Blepharotes splendidissimus (Wiedemann) (Asilinae: Apocleini). Taxonomically useful variation in asilid larvae so far described occurs in the head and its appendages. We have examined the fine detail of the larval head capsule and mouthparts using scanning electron microscopy (SEM) for the first time in Asilidae. The larva and pupa of B. splendidissimus are similar to other Asilidae but larger and more robust. The larva has a broad maxillae and long narrow mandibular hooks with an acute tip armed with a row of recurved spines. Our SEM studies detail the grooves on the inner surface of the mandible that form a feeding channel when the mandibles are appressed. Thus, the mandibular hooks are the insect equivalent of a Swiss army knife, with at least four functions: to pierce the prey, hold the prey, inject venom and extract nutrients from the prey. Asilid pupae have a well‐developed armature on the head, thorax and abdominal tergites, for drilling up out of the soil on adult eclosion. The pupa has distinct anterior and posterior antennal spinous processes and anterior and posterior mesothoracic spinous processes, and the tip of the abdomen has large, dorsally curved dorsal posterolateral processes and very small ventral posterolateral spinous processes. All the dorsal armature on the pupal abdominal segments are articulated spurs, rather than a mixture of fixed spines and spurs, as found in many asilid pupae.

Dietary Composition of Four Common Chiropteran Species in a Bottomland Hardwood Forest

Understanding foraging habits can be important for elucidating the ecology of any species and for designing appropriate conservation strategies. Common methods for determining bat diets, such as morphological examination of fecal material or recovery of prey fragments under feeding roosts, can be biased towards larger prey with harder exoskeletons by underestimating frequency/occurrence of smaller, softer bodied prey items. Our objectives were to determine prey selection for several common chiropteran species of bottomland hardwood forests in east Texas and to evaluate the use of DNA barcoding for dietary studies by comparing dietary composition to prey availability in four species of bats. We amplified the cytochrome coxidase subunit 1 gene from fecal samples collected from 19 bats of four species and identified arthropods by comparison to the Barcode of Life Data System database. We compared frequency of occurrence in fecal samples to frequency in concurrent night-flying insect sampling. We identified nine insect species from three orders consumed by Perimyotis subflavus, nine species from four orders consumed by Lasiurus seminolus, seven species from three orders consumed by Nycticeius humeralis, and 11 species from two orders consumed by Lasiurus borealis. Coleoptera was the most abundant order available by biomass, but beetles were never found in fecal samples from L. seminolus (n = 5) or L. borealis (n = 7) bats. However, Coleoptera comprised a substantial portion of prey identified from P. subflavus (n = 2) and N. humeralis samples (n = 5). Lepidopteran prey items were found in 13 of 19 bat fecal samples across all species but represented < 7% of arthropod biomass. Although dipteran species were a negligible portion (< 1%) of the available biomass, large numbers of dipterans were identified in fecal samples from all species of bats (13 of 19 samples across all species). Lasiurus seminolus and L. borealis may be selecting prey based on digestibility rather than availability; whereas, both N. humeralis and P. subflavus exhibited a more opportunistic approach to foraging. Based on comparison to other studies of bat diets, traditional techniques for analyzing diet from fecal samples are likely underrepresenting soft-bodied arthropods like dipterans.

Farnesol, a synomone component between lantana (Lamiales: Verbenaceae) and the omnivorous predator, Campylomma chinensis Schuh (Hemiptera: Miridae)

Flower scents are known as synomones between flowering plants and pollinators, but very little is known about the synomone involving omnivorous predator. Campylomma chinensis Schuh (Hemiptera: Miridae) is an omnivorous predator that feeds on both small soft-bodied arthropods and plant hosts including purple trailing lantana Lantana montevidensis (Spreng.) Briq. (Lamiales: Verbenaceae). In laboratory experiments, we examined the effect of fresh inflorescences and volatiles of L. montevidensis on the behavior of adult C. chinensis. In a Y-tube olfactometer, we found that the fresh inflorescences of L. montevidensis significantly attracted adult C. chinensis. Then, the volatile compounds from the fresh inflorescences of L. montevidensis were analyzed by gas chromatography coupled with mass spectrometry (GC–MS). The results showed that there were seventeen compounds detected in the inflorescences, and the main components were terpenoids including monoterpenoids and sesquiterpenoids. Moreover, the adults were significantly attracted to the concentration of 5 µl/ml farnesol. The results of the present work implied that the omnivorous mirid C. chinensis used farnesol, a sesquiterpenoid alcohol derivative, to identify and locate its plant hosts. The role of farnesol as a potential synomone for C. chinensis is discussed.

A Comprehensive Assessment of the Effects of Transgenic Cry1Ac/Cry1Ab Rice Huahui 1 on Adult Micraspis discolor (Fabricius) (Coleoptera: Coccinellidae).

Micraspis discolor (Fabricius) (Coleoptera: Coccinellidae) is a widely distributed coleoptera predator in southern Asia in rice ecosystem, and adult M. discolor feed on both rice pollen and soft-bodied arthropods. Bitrophic bioassay and tritrophic bioassay were conducted to evaluate the potential impact of Cry1Ac/Cry1Ab-expressing rice Huahui 1 and its non-transgenic counterpart Minghui 63 on fitness parameters of adult M. discolor. The results showed that the survival, and fecundity of this beetle’ adults were not different when they fed on Bt rice or non-Bt rice pollen or Nilaparvata lugens (Stål) reared on Bt rice or non-Bt rice. Toxicity assessment to ensure M. discolor adults were not sensitive to Cry1Ab or Cry1Ac protein independent from the pollen background, M. discolor adults were fed with an artificial diet containing Cry1Ac, Cry1Ab or both protein approximately 10 times higher concentration than in Huahui 1 rice pollen. No difference was detected for any of the life-table parameters tested between Cry protein-containing and pure diet. Artificial diet containing E-64 (N-(trans-Epoxysuccinyl)-L-leucine 4-guanidinobutylamide) was included as a positive control. In contrast, the pre-oviposition and fecundity of M. discolor were significantly adversely affected by feeding on E-64-containing diet. In both bioassays, the uptakes of Cry protein by adult M. discolor were tested by ELISA measurements. These results indicated that adults of M. discolor are not affected by Cry1Ab- or Cry1Ac-expressing rice pollen and are not sensitive to Cry protein at concentrations exceeding the levels in rice pollen in Huahui1. This suggests that M. discolor adults would not be harmed by Cry1Ac/Cry1Ab rice if Bt rice Huahui 1 were commercialized.

Green lacewings (of Florida) Neuroptera: Chrysopidae

The Chrysopidae are one of the largest and economically most important families of the Neuroptera. There are about 1,300 currently recognized species included in about 87 genera and three subfamilies (Brooks and Bernard 1990) in the world. In Florida, there are 22 species in 9 genera, all placed in the subfamily Chrysopinae (Penny et al. 1997). The larvae are voracious predators of small, comparatively soft-bodied arthropods such as aphids, scale insects, whiteflies, thrips, insect eggs, and other prey (Muma 1959; Canard et al. 1984). For this reason, they are used widely in biological control. The adults are usually predators, but a few species only feed on pollen. This 4-page fact sheet includes Key to the Genera of Green Lacewings of Florida. Written by Lionel A. Stange, and published by the UF Department of Entomology and Nematology, October 2012. EENY-534/IN965: Green lacewings (of Florida) (Insecta: Neuroptera: Chrysopidae) (ufl.edu)

Modeling locomotion of a soft-bodied arthropod using inverse dynamics

Most bio-inspired robots have been based on animals with jointed, stiff skeletons. There is now an increasing interest in mimicking the robust performance of animals in natural environments by incorporating compliant materials into the locomotory system. However, the mechanics of moving, highly conformable structures are particularly difficult to predict. This paper proposes a planar, extensible-link model for the soft-bodied tobacco hornworm caterpillar, Manduca sexta, to provide insight for biologists and engineers studying locomotion by highly deformable animals and caterpillar-like robots. Using inverse dynamics to process experimentally acquired point-tracking data, ground reaction forces and internal forces were determined for a crawling caterpillar. Computed ground reaction forces were compared to experimental data to validate the model. The results show that a system of linked extendable joints can faithfully describe the general form and magnitude of the contact forces produced by a crawling caterpillar. Furthermore, the model can be used to compute internal forces that cannot be measured experimentally. It is predicted that between different body segments in stance phase the body is mostly kept in tension and that compression only occurs during the swing phase when the prolegs release their grip. This finding supports a recently proposed mechanism for locomotion by soft animals in which the substrate transfers compressive forces from one part of the body to another (the environmental skeleton) thereby minimizing the need for hydrostatic stiffening. The model also provides a new means to characterize and test control strategies used in caterpillar crawling and soft robot locomotion.

A new Burgess Shale–type assemblage from the “thin” Stephen Formation of the southern Canadian Rockies

Research Article| September 01, 2010 A new Burgess Shale–type assemblage from the “thin” Stephen Formation of the southern Canadian Rockies Jean-Bernard Caron; Jean-Bernard Caron 1Department of Natural History-Palaeobiology, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario M5S 2C6, Canada Search for other works by this author on: GSW Google Scholar Robert R. Gaines; Robert R. Gaines 2Pomona College, Geology Department, 185 E. Sixth Street, Claremont, California 91711, USA Search for other works by this author on: GSW Google Scholar M. Gabriela Mángano; M. Gabriela Mángano 3Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada Search for other works by this author on: GSW Google Scholar Michael Streng; Michael Streng 4Department of Earth Sciences, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden Search for other works by this author on: GSW Google Scholar Allison C. Daley Allison C. Daley 4Department of Earth Sciences, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden Search for other works by this author on: GSW Google Scholar Geology (2010) 38 (9): 811–814. https://doi.org/10.1130/G31080.1 Article history received: 31 Jan 2010 rev-recd: 09 Apr 2010 accepted: 14 Apr 2010 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Jean-Bernard Caron, Robert R. Gaines, M. Gabriela Mángano, Michael Streng, Allison C. Daley; A new Burgess Shale–type assemblage from the “thin” Stephen Formation of the southern Canadian Rockies. Geology 2010;; 38 (9): 811–814. doi: https://doi.org/10.1130/G31080.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract A new Burgess Shale–type assemblage, from the Stephen Formation of the southern Canadian Rocky Mountains, is described herein. It occurs near Stanley Glacier in Kootenay National Park, 40 km southeast of the type area near Field, British Columbia. While at least a dozen Burgess Shale localities are known from the “thick” Stephen Formation, the Stanley Glacier locality represents the first discovery of Burgess Shale–type fossils from the “thin” Stephen Formation. The Cathedral Escarpment, an important regional paleotopographic feature, has been considered important to the paleoecologic setting and the preservation of the Burgess Shale biota. However, the Stanley Glacier assemblage was preserved in a distal ramp setting in a region where no evidence of an escarpment is present. The low-diversity assemblage contains eight new soft-bodied taxa, including the anomalocaridid Stanleycaris hirpex n. gen., n. sp. (new genus, new species). Nektonic or nektobenthic predators represent the most diverse group, whereas in relative abundance, the assemblage is dominated by typical Cambrian shelly benthic taxa. The low diversity of both the benthic taxa and the ichnofauna, which includes diminutive trace fossils associated with carapaces of soft-bodied arthropods, suggests a paleoenvironment with restrictive conditions. The Stanley Glacier assemblage expands the temporal and geographic range of the Burgess Shale biota in the southern Canadian Rockies, and suggests that Burgess Shale–type assemblages may be common in the “thin” Stephen Formation, which is regionally widespread. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Visceral-Locomotory Pistoning in Crawling Caterpillars

Animals with an open coelom do not fully constrain internal tissues, and changes in tissue or organ position during body movements cannot be readily discerned from outside of the body. This complicates modeling of soft-bodied locomotion, because it obscures potentially important changes in the center of mass as a result of internal tissue movements. We used phase-contrast synchrotron X-ray imaging and transmission light microscopy to directly visualize internal soft-tissue movements in freely crawling caterpillars. Here we report a novel visceral-locomotory piston in crawling Manduca sexta larvae, in which the gut slides forward in advance of surrounding tissues. The initiation of gut sliding is synchronous with the start of the terminal prolegs' swing phase, suggesting that the animal's center of mass advances forward during the midabdominal prolegs' stance phase and is therefore decoupled from visible translations of the body. Based on synchrotron X-ray data and transmission light microscopy results, we present evidence for a two-body mechanical system with a nonlinear elastic gut that changes size and translates between the anterior and posterior of the animal. The proposed two-body system--the container and the contained--is unlike any form of legged locomotion previously reported and represents a new feature in our emerging understanding of crawling.

Motor patterns associated with crawling in a soft-bodied arthropod

Soft-bodied animals lack distinct joints and levers, and so their locomotion is expected to be controlled differently from that of animals with stiff skeletons. Some invertebrates, such as the annelids, use functionally antagonistic muscles (circumferential and longitudinal) acting on constant-volume hydrostatics to produce extension and contraction. These processes form the basis for most theoretical considerations of hydrostatic locomotion in organisms including larval insects. However, caterpillars do not move in this way, and their powerful appendages provide grip independent of their dimensional changes. Here, we show that the anterograde wave of movement seen in the crawling tobacco hornworm, Manduca sexta, is mediated by co-activation of dorsal and ventral muscles within a body segment, rather than by antiphasic activation, as previously believed. Furthermore, two or three abdominal segments are in swing phase simultaneously, and the activities of motor neurons controlling major longitudinal muscles overlap in more than four segments. Recordings of muscle activity during natural crawling show that some are activated during both their shortening and elongation. These results do not support the typical peristaltic model of crawling, but they do support a tension-based model of crawling, in which the substrate is utilized as an anchor to generate propulsion.

Predatory arthropod assemblages of alfalfa and stinging nettle as potential biological control agents of greenhouse pests

We investigated alfalfa and stinging nettle from the point of view of their potential to supply natural enemies of pests for protecting greenhouse cultures. We carried out a three year long study based on sweepnetting. The most frequent predatory insect was Orius niger (Wolff) in alfalfa and nettle. This species among others has an important potential in the biological control of thrips. Among ladybugs, the most important species in alfalfa and nettle were Propylea quatuordecimpunctata (Linnaeus), Coccinella septempunctata Linnaeus and Hippodamia variegata (Goeze), which consume significant amounts of aphids. The most frequent spider family in alfalfa and nettle was Thomisidae and Philodromidae. The dynamics of their prey composition suggests that these taxa present a significant suppressive force on pests. The predator thrips Aeolothrips intermedius Bagnall that feeds on phytophagous thrips, mites and other soft-bodied arthropods was also significant in the arthropod assemblage of alfalfa. Our three-year...

First Record of The AntRhopalothrix weberi(Hymenoptera: Formicidae: Myrmicinae) for Mexico

The genus Rhopalothrix Mayr is a member of the monophyletic tribe Basicerotini (Bolton 1998). It is a rare group of ants with 10 known species, 7 of which are distributed across Central and South America and the rest in the Indo-Aus tralian region. The biology of this genus is not well known, but it seems to exhibit the same predatory habits as other members of the tribe; the few basicerotines whose habits are known are predators of small, soft-bodied arthropods (Wil son 1956; Brown & Kempf 1960; Wilson & Brown 1985; Longino 1999). Ants of this genus have 7-segmented antennae that, when reclined against the head in their nor mal position, are sustained on the antenn?i scrobes that run beneath the eyes. Their mandi bles are slender and elongate; when completely shut, they remain separated due to a cavity that runs along most of their length and touches only at the tips. These ants are similar to Eurhopalo thrix, but with thinner, more elongate, triangular jaws. In this paper we report the first record of Rho palothrix weberi Brown and Kempf for Mexico. Until now, the only known record of the genus in this country was for R. stannardi in the state of Chiapas (Brown & Kempf 1960). During a sam pling project to study the ant fauna associated with patches of cloud forest in the central part of the state of Veracruz, 1 worker of this species was collected from a litter sample processed in Win kler bags. Although we processed more than 120 samples of litter from cloud forest and coffee plan tations in this zone, only 1 specimen was ob tained. The collection of these ants tends to be quite scattered; as in this case, they are generally found as isolated individuals obtained from litter samples processed in Winkler traps or Berlesse funnels (Longino 1999; Brown & Kempf 1960). The R. weberi worker was collected near El Olmo, situated on the road between Teocelo and Ixhuacan de Los Reyes in the municipality of the same name (latitude 19 20 5 ; longitude 97?01' 42W), at an altitude of 1300 m (Aug 12, 2008, J. Valenzuela Col.). It was sampled in a patch of cloud forest of about 8 ha located on hilltops sur rounded by coffee plantations. The ant was identified with keys and descrip tions provided by Brown & Kempf (1960) as well as Weber's original description of this species, as Heptastruma wheeleri (Weber 1934). The speci men has the following features characteristic of the description of R. weberi. The dorsum of head with a pair of well-defined transverse ridges; clypeus without conspicuous subappressed, oval setae; labrum with a deep median cleft or notch that extends inward from its apex nearly to its midlength with rounded lateral lobes (Fig. 1);

Preservation of early and Middle Cambrian soft-bodied arthropods from the Pioche Shale, Nevada, USA

The Early–Middle Cambrian Pioche Shale of Lincoln County, Nevada preserves a diverse array of soft-bodied ecdysozoans that are well-known from the Burgess Shale soft-bodied fauna of British Columbia, Canada. At Pioche certain genera occur both above and below the Middle Cambrian boundary, allowing a comparison of the nature of their preservation across this interval. In order to investigate the mineralization of this fauna, SEM analysis of mineral textures and element mapping of Anomalocaris, Tuzoia and Canadaspis specimens using energy dispersive X-ray spectroscopy (EDS) was undertaken. Results of these analyses show that Early Cambrian specimens are generally preserved in botryoidal hematite which is dark red in hand specimen while specimens from the Middle Cambrian are preserved as kerogenized carbon films with associated oxidized pyrite crystals and framboids. Comparison with other Cambrian soft-bodied biotas reveals that the nature of preservation of the Middle Cambrian biota at Pioche is remarkably similar to that described for the Chengjiang soft-bodied fauna, China. There does not seem to be an adequate analogue for the Early Cambrian preservation of soft-bodied organisms at Pioche. The preservation of the fauna is discussed in relation to changing environmental conditions at the Early–Middle Cambrian boundary.