Nesting behavior of the semi-aquatic spider wasp,Anoplius eous,which transports its prey on the surface film of water (Hymenoptera,Pompilidae)

Anoplius eous Yasumatsu (Hymenoptera, Pompilidae) exhibits some outstanding nesting behavior. Females excavate a unicellular or multicellular nest in wet ground, or dig a single-celled nest in rotten wood, or build clustered mud cells in narrow spaces between walls of such substances as wood or vinyl sheets. The latter nest-type has been unknown within the subfamily Pompilinae. Females prepare a nest-cell before hunting, and construct it further after hunting, leaving the prey near the nest (behavior-formula: IVPTIOC). They transport their prey backward on the ground, grasping it in their mandibles by any part of the legs, and forward on the surface film of water or on the ground, grasping it by the middle part of the 1st or 2nd legs. Their only prey is the adult female semi-aquatic spider,Pardosa pseudoannulata (Lycosidae). These nesting and provisioning behavior patterns are compared with those of other pompilids. The position of the present species in the behavioral evolution of the Pompilidae is suggested.     

Preliminary morphological analysis of relationships between the spider wasp subfamilies (Hymenoptera: Pompilidae): revisiting an old problem

No qualitative cladistic analysis has been performed previously for the subfamily classification of Pompilidae (Hymenoptera). In 1994 Shimizu proposed six subfamilies, but their validity and relationships remain inconclusive. The objective of this study was to perform a quantitative analysis of phylogenetic relationships of the Pompilidae, with emphasis on testing the validity of proposed subfamilies. Two cladistic analyses were performed based on morphological evidence. First, a maximum-parsimony analysis of Shimizu's original morphological data matrix (72 taxa by 54 characters) was conducted, with the data subjected to a heuristic search for the first time with phylogenetic software. The resulting strict-consensus cladogram yielded a monophyletic Ceropalinae that was sister group to a large polytomy containing members of the remaining five subfamilies. In a second analysis, several of Shimizu's characters were re-examined, and new characters and more taxa were added to the data set. Terminal taxa were coded as species rather than as generic abstractions, and 20 additional morphological characters were introduced. The analysis was based on 77 morphological characters derived from the adults of 84 taxa. This second analysis suggested that Notocyphinae sensu Shimizu (1994) was nested within Pompilinae and that Epipompilinae sensu Shimizu (1994) was nested within Ctenocerinae; neither should retain their status as a separate subfamily. Lastly, Chirodamus s .s., which historically has been a member of the Pepsinae, is placed within the Pompilinae with reservations rather than erecting a new subfamily. After these allowances were made, a strict consensus tree gave the following relationships: (Ceropalinae + (Pepsinae + (Ctenocerinae + Pompilinae))).     

Species-Specificity of Chemical Signals: Silk Source Affects Discrimination in a Wolf Spider (Araneae: Lycosidae)

Female spiders deposit chemical cues that elicit male courtship behavior with silk. These cues are often assumed to be species-specific although male spiders may court in response to chemical cues of closely-related species. We used behavioral assays to test the extent of species discrimination of female chemical cues by male Schizocosa ocreata, a wolf spider (Lycosidae). Discrimination, expressed as relative courtship intensity of males, varied significantly with phylogenetic distance. Males did not discriminate between female cues of conspecifics and a sibling species, S. rovneri. Courtship response was intermediate for another species within the ocreata clade and not different from control for spiders outside the clade. These findings support the sibling species status of S. ocreata and S. rovneri, and also suggest the composition of female chemical signals is conserved across closely related wolf spider species.     

Phylogenetic revision of the parasitoid wasp family Trigonalidae (Hymenoptera)

A phylogenetic analysis of generic relationships and revised generic concepts for the Trigonalidae is presented. The Trigonalidae is divided into two subfamilies, the Orthogonalinae and the Trigonalinae. Orthogonalinae consists of a single primitive genus, Orthogonalys, sharing many generalized apocritan characters, but lacking advanced trigonalid characters including antennal tyloids and female metasomal armature. No synapomorphies have been detected for the Orthogonalinae. Trigonalinae are characterized by the presence of tyloids. The Trigonalinae were originally defined by the absence of female armature, and were therefore polyphyletic because armature has been lost several times. Within the revised concept of Trigonalinae, the tribe Trigonalini is characterized by the presence of elongate parameres and an intertorulus distance subequal to the distance between the torulus and the eye. A second tribe, Nomadinini, is based on the secondary loss of tyloids, and comprises the previous subfamilies Seminotinae, Nomadininae, Bareogonalinae and Lycogastrinae. The two tribes Trigonalini and Nomadinini share the presence of female armature, although in some Trigonalini it has been secondarily lost. The genera Labidogonalos Schulz, Lycogastroides Strand, Lycogonalos Bischoff, Nanogonalos Schulz, Poecilogonalos Schulz and Taiwanogonalos Tsuneki are synonymised under Taeniogonalos Schulz. The species Lycogaster zimmeri Bischoff, Tapinogonalos maschuna Schulz, and Trigonalys pictifrons Smith (placed in Lycogaster by Schulz, 1906a) are transferred to Taeniogonalos. The genera Discenea Enderlein and Stygnogonalos Schulz are synonymised under Trigonalys Westwood. The species Labidogonalos flavescens Bischoff, L. sanctaecatharinae Schulz, Trigonalys lachrymosa Westwood (placed in Lycogaster by Bischoff, 1938), T. maculifrons Cameron (placed in Labidogonalos by Bischoff, 1938) and T. rufiventris Magretti (placed in Lycogaster by Schulz, 1907a) are transferred to Trigonalys.Trigonalys costalis Cresson is synonymised with Taeniogonalos gundlachii (Cresson). Xanthogonalos fasciatus Bertoni and X.severini Schulz are synonymised with Trigonalys sanctaecatharinae (Schulz). Mimelogonalos partiglabra Riek and M. punctulata Riek are synonymised with M. bouvieri Schulz. Lectotypes are designated for Trigonalys melanoleuca Westwood and Taeniogonalos fasciatipennis (Cameron). The author of Trigonalys maculifrons is Sharp (1895), not Cameron (1897), and the author of Taeniogonalos enderleini is De Santis (1980), not Schulz 1906. Viereck (1914) designated Trigonalys pulchella Cresson as type of the genus Tapinogonalos Schulz, preceding Bischoff's (1938) designation, making Tapinogonalos a synonym of Orthogonalys. A new genus, Afrigonalys, is proposed for the three species that were described in ‘Tapinogonalos’sensu Bischoff, nec Viereck.     

Single-locus sex determination in the parasitoid wasp Cotesia glomerata (Hymenoptera: Braconidae)

The parasitoid Cotesia glomerata usually produces female-biased sex ratios in the field, which are presumably caused by inbreeding and local mate competition (LMC); yet, sibling mating increases the production of males, leading to the male-biased sex ratio of broods in the laboratory. Previous studies have suggested that the sex allocation strategy of C. glomerata is based on both partial LMC in males and inbreeding avoidance in females. The current study investigated the presence of single-locus complementary sex determination (sl-CSD) as a sex-determining mechanism in this species through inbreeding experiment, cytological examination and microsatellite analysis. Cytological examination detected diploid males in nine of 17 single pairs of sibling mating, thus in agreement with the proportion of matched matings predicted by the sl-CSD model. Sex ratio shifts in these matched sibling matings were consistent with the sl-CSD model with less viable diploid males. The haploid males have a single set of maternal chromosomes (n = 10), whereas diploid males possess a double set of chromosomes (2n = 20). Microsatellite analyses confirmed that diploid males produced from the matched matings inherited segregating genetic materials from both parents. Thus, this study provides the first solid evidence for the presence of sl-CSD as a sex-determining mechanism in the braconid genus Cotesia.     

Brood Parasitism in Two Species of Spider Wasps (Hymenoptera: Pompilidae, Dipogon), with Notes on a Novel Reproductive Strategy

A trap-nesting study provided the first documentation of brood parasitism in Dipogon nagasei and in D. iwatai. Dipogon nagasei was found to brood parasitize D. sperconsus, D. conspersus, D. inconspersus, and D. bifasciatus. Dipogon iwatai brood parasitized D. sperconsus, D. conspersus, D. romankovae, and Auplopus carbonarius. Both brood parasitic species are with the subgenus Nipponodipogon, whereas all five Dipogon hosts are in the subgenus Deuteragenia. Comparison of their ecological features revealed that brood parasitism in D. nagasei is considerably more derived than in D. iwatai. Of particular note is the fact that in D. nagasei the female routinely lays up to five eggs on a single host spider, all of which develop into adult wasps without larval cannibalism; almost all Pompilidae previously studied lay only one egg on a host spider.     

Silk production in adult females of the Wolf spider Pardosa amentata (Lycosidae, Araneae)

The production of silk in adult females of the wolf spider Pardosa amentata (CI.) has been studied. The role of female silk in courtship behavour is discussed on teh basis of experimental data.     

The rearranged mitochondrial genome of Podagrion sp. (Hymenoptera: Torymidae), a parasitoid wasp of mantis

The complete sequence of the mitochondrial genome of Podagrion sp. (Hymenoptera: Torymidae) is described. The mitogenome was 15,845 bp in size, and contained typical sets of mitochondrial genes. The base composition of the Podagrion sp. mitogenome was also biased toward A + T bases (81.8%). The mitochondrial genome of Podagrion sp. has a weak AT skew (0.07) and a strong GC skew (?0.26). Podagrion sp. exhibits a novel rearrangement compared with the ancestral order, including six protein-coding genes (nad3, cox3, atp6, atp8, cox2 and cox1), which have inverted to the minor strand from the major strand. The A + T-rich region of Podagrion sp., which is located between trnN and trnI, have five tandem repeats. The apomorphic rearrangements, including the conserved block “cox3-atp6-atp8-cox2-cox1-nad5-nad4-nad4l-nad6-cob” and the special locations of trnV and trnA, were mapped onto the phylogeny of Proctotrupomorpha.     

Absence of social facilitation of courtship in the wolf spider, Schizocosa ocreata (Hentz) (Araneae: Lycosidae)

Males of many animal species are reproductively limited by the difficulty and time costs of finding mates. Males of such species should be selected to take advantage of any cues that might reveal the location of prospective mates. Cues to female location are not restricted to those produced by females, but might also include the highly apparent courtship displays of males that have already found a female. By “eavesdropping” on these courting rivals, initiating sexual displays when courting rivals are detected (i.e., social facilitation of displays); males might effectively exploit the mate-searching efforts of their rivals. We tested the possibility that male Schizocosa ocreata wolf spiders exhibit social facilitation of courtship behaviors using a combination of live behavioral trials and video playback with single stimulus presentations. When exposed to visual cues from another male, male S. ocreata can discern the presence of another individual whether that individual is courting or not. However, we found no evidence of social facilitation of courtship or chemoexploratory behaviors in response to seismic or visual cues presented in isolation or combined. While complex, multimodal, male courtship signals are important in mate choice by female S. ocreata, males do not appear to use these cues to socially facilitate their own courtship.     

Preference for Chemical Cues Associated with Recent Prey in the Wolf Spider Hogna helluo (Araneae: Lycosidae)

In the wolf spider, Hogna helluo , we tested the response to insect and spider prey chemical cues and whether they show a preference for cues associated with prey consumed most recently. Thirty adult female H. helluo were maintained on a diet of either females of a smaller co-occurring wolf spider ( Pardosa milvina ) or domestic crickets ( Acheta domesticus ). A single P. milvina or cricket nymph was maintained on filter paper for 24 h, after which the papers from both prey sources were simultaneously presented to individual H. helluo from each diet treatment group. H. helluo locomotor behavior on each treatment and initial substrate preference was recorded (n = 15/treatment). H. helluo fed crickets showed significantly longer residence time and decreased mobility on filter paper previously occupied by a cricket; spiders fed P. milvina showed longer residence times and decreased mobility on filter paper previously occupied by P. milvina . H. helluo fed P. milvina exhibited an initial preference for substrates previously occupied by P. milvina but H. helluo fed crickets did not show a corresponding initial preference for crickets. Results suggest that H. helluo can detect distant cues associated with P. milvina but not crickets before contacting the substrate and that H. helluo respond to chemical cues from prey and show a preference for those cues associated with their most recent prey.     

Spider prey (Araneae) of Trypoxylon (Trypargilum) rogenhoferi (Hymenoptera: Sphecidae) in southeastern Brazil

Fifty five nests and 216 cells of Trypoxylon (Trypargilum) rogenhoferi were obtained from trap-nests (cut bamboo canes) in Santa Carlota Farm (Itaoca Section = IS and Santana Section = SS), Cajuru and on the S?o Paulo University Campus, Ribeir?o Preto (= RP), both in the State of S?o Paulo, Brazil (Sept. 1993-Oct. 1995). The prey (spiders) of 40 cells from IS, 58 from SS and 39 from RP were identified. The greatest nesting frequency occurred during the hot and wet season (September to April). T. rogenhoferi preyed upon individuals of five spider families, with Araneidae (orb-weaver spiders) being the most frequent (99.6%). Alpaida aff. negro (58%) was the most frequently collected species in IS, followed by A. alto (24.8%); in SS (59.6%) and RP (64.7%) the most frequent species was A. veniliae, followed in SS by A. aff. negro (14.9%) and in RP by A. leucogramma (13.5%). The size of reproductive niches, H' = 1.25 (IS), H' = 1.30 (SS) and H' = 1.29 (RP) were not significantly different. There was a positive correlation between the reproductive niche width (H') and evenness.     

Microhabitat selection and audible sexual signalling in the wolf spider Hygrolycosa rubrofasciata (Araneae, Lycosidae)

We studied the microhabitat selection and male sexual signalling behaviour in the wolf spider Hygrolycosa rubrofasciata (Ohlert). Males strike dry leaves with their abdomen, producing an audible sexual drumming signal, and females use this signal to choose mating partners. In the field we followed male drumming rate and microhabitat selection using both the mark–recapture method and direct observations. In the laboratory we conducted an experiment on male microhabitat and drumming substrate selection. We found that in the field males were not distributed randomly among the habitat; fewer males were found in areas that had high sedge cover, low elevation, and low dry leaf cover. In the laboratory experiment, males spent more time on dry leaf substrate. Drumming rate in the field was positively correlated with dry leaf cover and in the laboratory males clearly preferred dry leaves as drumming substrate. Temperature was positively correlated with male drumming rate, and with male and female mobility. We conclude that in H. rubrofasciata male distribution and sexual signalling rate, and thus mating success, are greatly affected by environmental factors. Therefore, males may be sexually selected to make effective use of their signalling habitat by active microhabitat choice. Received: 27 December 1999 / Received in revised form: 14 February 2000 / Accepted: 14 February 2000     

Effect of cold storage of pupae parasitoid wasp,Habrobracon hebetor (Say) (Hymenoptera: Braconidae), on its efficiency

Cold storage is an appropriate way to extend the life of natural enemies such as insect parasitoids. Identification of risk factors for use in biological control and replacing it instead of chemical control is important, and therefore wasp species of genus Bracon have been used for controlling various pests in the past and present. The aim of this study was to determine the optimum temperature and time of storage of parasitoids pupae, Habrobracon hebetor (Say) in cold conditions. After in vitro rearing of the insect, the pupae of H. hebetor at the temperatures of 12, 9 and 4?°C for a period of six weeks in five replicates were stored. After these times, the effect of storage on the percentage of emerged adults and the longevity of male and female adults was evaluated on a weekly basis. The results of the survey conducted at 12?°C showed that the percentage of adults emerged from the first week has dropped by almost half. H. hebetor pupae could be stored for a week at 9?°C. At 4?°C, a significant reduction was caused in the efficacy of the stored pupae and is not recommended.     

Mariapanteles (Hymenoptera, Braconidae), a new genus of Neotropical microgastrine parasitoid wasp discovered through biodiversity inventory

A new genus of microgastrine parasitoid wasps, Mariapanteles Whitfield & Fernández-Triana, gen. n., is described from rain forests of the Neotropics. The new genus is related to the common and speciose genus Pseudapanteles, but can be distinguished from the latter by having a complete transverse carina on the propodeum which forks around the spiracles. A molecular analysis based on data from COI from specimens of the proposed new genus plus possibly related genera confirms its generic distinctness. A key to two known species, Mariapanteles felipei Whitfield, sp. n. (Costa Rica) and Mariapanteles dapkeyae Fernández-Triana, sp. n. (Brazil) is provided. Evidence from collections suggests that there are other undescribed Neotropical congenerics. Specimens of Mariapanteles were likely confused in the past with the genus Beyarslania (referred to as Xenogaster until recently) but present information suggests that Beyarslania is restricted to the Afrotropical region while the Neotropical species clearly belong to a different genus, which we propose as new.     

Combined molecular and morphological phylogenetic analyses of the New Zealand wolf spider genus Anoteropsis (Araneae: Lycosidae)

Datasets from the mitochondrial gene regions NADH dehydrogenase subunit I (ND1) and cytochrome c oxidase subunit I (COI) of the 20 species in the New Zealand wolf spider (Lycosidae) genus Anoteropsis were generated. Sequence data were phylogenetically analysed using parsimony and maximum likelihood analyses. The phylogenies generated from the ND1 and COI sequence data and a previously generated morphological dataset were significantly congruent (p<0.001). Sequence data were combined with morphological data and phylogenetically analysed using parsimony. The ND1 region sequenced included part of tRNA(Leu(CUN)), which appears to have an unstable amino-acyl arm and no TpsiC arm in lycosids. Analyses supported the existence of five species groups within Anoteropsis and the monophyly of species represented by multiple samples. A radiation of Anoteropsis species within the last five million years is inferred from the ND1 and COI likelihood phylograms, habitat and geological data, which also indicates that Anoteropsis arrived in New Zealand some time after it separated from Gondwana.     

Functional and nonfunctional female receptivity signals in the parasitoid wasp Spalangia endius (Hymenoptera: Pteromalidae)

In many taxa, females signal during courtship when they are receptive. However, just because a female signals does not mean that the male responds to the signal. This study examines female signaling of receptivity (readiness to copulate) and male response in the parasitoid wasp Spalangia endius Walker. Females folded their antennae against their heads when they were receptive, and antennal folding has been shown to be effective in eliciting male copulation attempts in a confamilial. However, male S. endius did not respond to antennal folding: males did not contact the female's antennae during courtship, and how quickly a male attempted copulation was independent of whether or not the female had antennae. Males courted from on top of the female's abdomen and appeared to detect receptivity directly from the female's abdomen rising as her genital orifice opened. On females whose abdomens did not rise, initiation of male copulation attempts were delayed but not eliminated. Based on its current lack of function as a receptivity signal and on comparisons to published reports of mating behavior in confamilials, we hypothesize that female antennal folding at receptivity is a vestigial trait in S. endius.     

The Effect of Predator Chemical Cue Age on Antipredator Behavior in the Wolf Spider Pardosa milvina (Araneae: Lycosidae)

The wolf spider, Pardosa milvina, exhibits reduced movement when detecting chemical cues (silk and excreta) from a larger wolf spider, Hogna helluo. We tested if cue age influenced Pardosa activity. Pardosa response was measured during 1-h trials using video-tracking equipment. Five treatments of predator cues were used: 5-day-old, 1-day-old, 1-h-old, and fresh cues and a control lacking predator cues. Pardosa moved significantly more slowly on substrates with fresh or 1-h-old cues compared to all other treatments and spent less time walking in all Hogna treatments relative to the control except with 5-day-old cues. Pardosa survived longer in the presence of Hogna with fresh compared to older cues. Prey may evaluate cue age as a measure of predation risk and grade antipredator behavior accordingly.