Solitary Wasp Species Research Articles

Stem-nesting Hymenoptera in Irish farmland: empirical evaluation of artificial trap nests as tools for fundamental research and pollinator conservation

Insect pollinators are suffering global declines, necessitating the evaluation and development of methods for long-term monitoring and applied field research. Accordingly, this study evaluated the use of trap nests (“bee hotels”) as tools for investigating the ecology of cavity nesting Hymenoptera within Irish agricultural landscapes. Three trap nests consisting of 110 mm diameter plastic pipe containing 100 cardboard nest tubes of varying diameter were placed at eight apple orchards and eight oilseed rape sites and left in the field for five months. Sealed nest tubes occurred at 15 of the 16 sites, and in 77% of the 48 nests. However, only 7% of the 4800 individual nest tubes were sealed, and only 4% produced cavity-nesting Hymenoptera. Three cavity nesting bee species (Hylaeus communis, Osmia bicornis, Megachile versicolor) and two solitary wasp species (Ancistrocerus trifasciatus, A. parietinus) emerged from nest tubes. There were significant differences among species in terms of emergence date and the diameter of nest tubes from which they emerged, the latter allowing the calculation of niche width and niche overlap, and informing choice of tube size in future studies/conservation efforts. Trap nests, therefore, offer a valuable tool for fundamental ecological research and a model system for investigating interactions between stem-nesting species within their wider ecological networks. The ability of trap nests to actually increase farmland pollinator abundance and diversity as part of agri-environment schemes requires additional investigation. However, used in sufficient numbers, these trap nests provide valuable biogeographical data for cavity nesting Hymenoptera and offer a viable means for long term monitoring of these species in Irish farmland.

Brood reduction caused by sibling cannibalism in Isodontia harmandi (Hymenoptera: Sphecidae), a solitary wasp species building communal brood cells.

Sibling rivalry or brood reduction prevailing within bird nests is effectively avoided in solitary aculeate nests because the larvae of wasps and bees usually develop in each brood cell. However, a solitary wasp species, Isodontia harmandi, allows us to study brood reduction in a communal brood cell, where up to a dozen larvae develop in a group relying on prey provisioned by a female wasp. To demonstrate brood reduction in this species, we collected nests at various developmental brood stages from fields for five years (2010–2015). There was a significant decrease in the brood size between the nests sampled at the egg or hatchling stages and those at later stages when analyzing only data excluding nests that were parasitized, attacked by predators, or containing deteriorated prey. In whole brood-rearing experiments, we also confirmed that brood reduction occurred in 30 of 39 nests during larval stages and in 23 nests after cocoon stage. Larval survival was affected positively by total prey weight and negatively by brood size, though cocoon survival was not affected. A third-quarter (76%) of larval death was identified as sibling cannibalism through observation by time-lapse recording on multi-larvae rearing experiments. Therefore, we conclude that brood reduction routinely occurs as a result of sibling cannibalism in I. harmandi. Additionally, as we could not detect any positive effects of clutch size on the amount of provision, female wasps might overproduce offspring due to the unpredictability of available prey resources. Differences in brood size and reduction among sex categories were undetected, except for parental provisions. Thus, sibling cannibalism may efficiently regulate brood size in communal brood cells under prey shortage.

A new species of Lestica Billberg (Hymenoptera: Crabronidae) from Turkey

A new solitary wasp species, Lestica anatolica Can et Glmez, is described and illustrated based on a male from Sivas province of Turkey. This species is similar to L. clypeata (Schreber, 1759) but distinguished from it by the presence of a transparent spine on the apex of foretrochanter instead of carina and dilatation in all of the first three foretarsomeres (foretarsomeres II and III distinctly narrower than I in L. clypeata). Additionally, new locality records are given for two previously known species in Turkey, L. clypeata and L. subterranea (Fabricius, 1775). An identification key is provided for the species of Lestica Billberg, 1820 occurring in Turkey.

Reproductive success of Trypoxylon (Trypargilum) lactitarse (Hymenoptera: Crabronidae) in a fragmented landscape

ABSTRACT Fragmentation of natural vegetation often implies a reduction in local species richness and abundance. The resources used by bees and wasps for feeding and nesting are distributed quite irregularly in fragmented environments, which influences their foraging behavior, occurrence patterns and reproductive success. The objective of the present work was to determine if the size of native vegetation remnants influences the reproductive success of the solitary wasp species Trypoxylon (Trypargilum) lactitarse Saussure, 1867. Trap-nests were established along the edges of forest fragments of different sizes located in municipalities in the central region of the state of Goiás, Brazil. The nests were used to quantify nesting rate, number of cells with larvae, survival of larvae, proportion of nests attacked by parasitoids, and size of hatched adults. The foundation rate of trap-nests was greater in large fragments, whereas the mean number of cells per nest, parasitoidism rate, larval survival and sex ratios, and size of hatched adults did not differ between large and small fragments. Therefore, it appears that fragment size influences the survival or permanence of adults more so than it does that of the larvae in the studied fragments. There are two possible explanations for the difference in the foundation rate: 1) each female founds, in average, the same number of nests in small and large fragments, but the number of females is lower in the smaller fragments; 2) females have the capacity to provision several nests, but in the larger areas each female founds more nests than in smaller areas. However, it is necessary future studies to differentiate these two hypotheses.

Solitary wasp diversity (Hymenoptera: Aculeata) in different cultivation environments

ABSTRACT: Wasps contribute to environmental quality and ecosystem services, and play a key role in the functioning of many environments. The present study identified the diversity of species of solitary wasps that occupied trap-nests in farming environments. as well as the architecture of the nests found. The study focused on three areas of agroecosystem, where 30 blocks of trap-nests, with four diameters (5 mm, 7 mm, 9 mm, and 11 mm), were installed. A total of 56 nests were occupied by solitary wasps, with the most frequent species being Trypoxylon sp.1 (N=100, 54.9%), Pachodynerus cf. brevithorax (N=31, 17.0%), Trypoxylon sp.2 (N=27, 14.8%) and Caenochrysis nigropolita (N=9, 4.9%). The wasps occupied preferentially the trap-nests of 5 mm and 7 mm in diameter. Six wasp families were recorded, with the most abundant being the Crabronidae with 127 individuals, followed by the family Vespidae (N=36). Reduced number of species was recorded in the study area with frequent use of pesticides, and farming practices, which may damage nesting sites. These findings provide important guidelines for the use of agricultural practices, and emphasize the need for the adoption of effective strategies for the conservation and sustainable management of the populations of these potentially beneficial insects.
 KEY-WORD: Conservation, hymenopterans, agroecosystems.

Teratology in the solitary wasp family Sphecidae (Insecta: Hymenoptera)

In this study, forewing teratology in 42 species of solitary wasps belonging to the family Sphecidae (Hymenoptera) collected from various provinces of Turkey were investigated for the first time. In total, 20 cases of wing venation anomalies, classified as: a) irregular vein course, b) supernumerary veins, c) defective veins and d) supernumerary cells, were observed in 112 of 1682 specimens. The most encountered wing venation anomalies were: a spur protruding from 1 m-cu to 1st discoidal cell (n = 42, 37.50%), an incomplete 1r-m cross-vein (n = 21, 18.75%), and completely reduced 1r-m cross-vein (n = 10, 8.92%). The anomalies were rather common in the species Podalonia fera (n = 19, 36.53%), P. luffi (n = 11, 33.33%), P. hirsuta (n = 18, 33.33%) and Chalybion walteri (n = 1, 33.33%). In general, anomalies were more frequently observed in male wasps (n = 65, 58.03%). Teratology could be caused by genetic, environmental or pathogenic factors.

An overview of the mite fauna (Acari) associated with eumenine wasps (Hymenoptera: Vespidae) found in Brazilian collections

ABSTRACTMites can be associated with other organisms as parasites, commensals, phoretic, among others, such as some Winterschmidtiidae that present cooperative relationships with solitary wasps (Eumeninae). These wasps have one or more cavities in their body surface that are capable of carrying mites, called acarinaria. Studies carried out in the northern hemisphere suggest that these relationships are species-specific. However, in South America, there are few studies in this field. Aiming to recognize and increase our knowledge of the species of solitary wasps from Brazil that are associated with mites, we examined 61 wasps belonging to 29 species and four genera from Brazilian museum collections. All of the specimens studied presented at least one type of acarinarium in their bodies. There were mites in all specimens of wasps, but not all of them were associated with an acarinarium. The mites belong to 11 different genera: six in Winterschmidtiidae (possibly cooperation relationships); one in Oplitidae (phoresy); one in Erythraeidae (parasitism); two in Acaridae (phoresy); and one in Histiostomatidae (phoresy). Detrended correspondence analysis and indicator species analysis were conducted to test the preference of the mite genera for species of wasp and for site (regions of the wasp’s body). These tests were significant only for the mite genus Vespacarus preferring Parancistrocerus wasp species and the metasomal acarinaria. Some of the mites did not have a specific host, and some wasps carried more than one species of mite, differing from the specific interactions reported for the northern hemisphere.

Isolation and characterization of microsatellite loci for the mud-dauber wasp Trypoxylon (Trypargilum) albitarse (Hymenoptera: Crabronidae)

This paper describes the characterization of a set of nine microsatellite markers for the pipe-organ mud-dauber wasp, Trypoxylon albitarse F. (Hymenoptera: Crabronidae), a common solitary wasp species in Brazil. Eight of the nine loci described were found to be polymorphic. The number of alleles ranged from three to 11. Observed and expected heterozygosity on the population level ranged from 0.135 to 0.891 and 0.177 to 0.865, respectively. Genotypic analyses revealed no deviations from Hardy-Weinberg equilibrium or linkage disequilibrium after sequential Bonferroni correction. Cross-species amplification was also tested for nine related species and positive amplifications were found in most of the assays. These markers will be useful in studies involving relatedness analysis and investigations of the population genetics of these wasps.

Effects of Male Size on Searching Behaviors in the Sun Dance ofBembix

Males of solitary wasp species are faced with the task of locating potential mates, a task made more difficult by inconspicuous females and a landscape seemingly devoid of landmarks. Males may employ a variety of strategies to locate females. In this study, we test for variation among males within the sun dance of Bembix. We show that males of Bembix americana spinolae Lepeletier behave differently within the sun dance and that these differences can be predicted by the size of the male. We show that large males spend more time at “rest” and require a greater number of male-male contacts to be displaced from rest than small males. This difference in mate location strategy, however, appears to be density dependent, as large and small males in small aggregations exhibit no difference in the strategies they employ.

The nest structure in four species of solitary wasps of the subfamily Eumeninae (Hymenoptera, Vespidae)

Nests of Syneuodynerus egregius, Euodynerus posticus, Ancistrocerus antilope, and A. nigricornis have a similar structure and consist of a linear row of cells separated by transverse partitions made of soil mastic. The number of cells in the nests is 1–11 (5.6 ± 0.8) in S. egregius, 1–7 (2.6 ± 0.2) in E. posticus, 1–10 (4.0 ± 0.7) in A. antilope, and 1–28 (7.9 ± 1.3) in A. nigricornis. Most nests consist of several cells in S. egregius and A. nigricornis and of one or two cells in E. posticus and A. antilope. The female to male ratio is 1.2: 1.0 in E. egregius, 1.5: 1.0 in E. posticus, 1.9: 1.0 in A. antilope, and 1.0: 1.0 in A. nigricornis. The nests of S. egregius usually contain brood of both sexes; those of A. antilope, that of one sex. The sex ratio is correlated with the diameter of the occupied nest cavities only in A. antilope. The volume of the cells with females exceeds that of the cells with males in all the species studied: by 23, 34, 54, and 98% in S. egregius, E. posticus, A. antilope, and A. nigricornis, respectively. The relative difference between the body masses of male and female prepupae is correlated with the relative difference between the volumes of their cells. The nest cells of S. egregius are separated by double partitions consisting of homologs of cell bottoms and lids. In the nests of E. posticus the partitions are single; each cell has a bottom and a lid, with “false cells” being located between them. In the nests of A. antilope and A. nigricornis, the partitions are single but all of them are homologs of the cell bottoms. The nest cells of S. egregius belong to the equilinear type; their length is relatively constant in the cavities of various diameters. The nest cells of A. antilope are of the equivolumetric type: their length is smaller in broad cavities and greater in narrow ones, the cell volume being relatively constant in the cavities of different diameters. The nest cells of E. posticus and A. nigricornis are of the intermediate type. Statistical models of nests reflecting their mean parameters and composition were built. The evolutionarily primitive and progressive features in the nest structure are discussed.

Refining the Roots of the Beewolf-Streptomyces Symbiosis: Antennal Symbionts in the Rare Genus Philanthinus (Hymenoptera, Crabronidae)

Insects engage in symbiotic associations with a large diversity of beneficial microorganisms. While the majority of well-studied symbioses have a nutritional basis, several cases are known in which bacteria protect their host from pathogen infestation. Solitary wasps of the genera Philanthus and Trachypus (beewolves; Hymenoptera, Crabronidae) cultivate the actinomycete "Candidatus Streptomyces philanthi" in specialized antennal gland reservoirs. The symbionts are transferred to the larval cocoon, where they provide protection against pathogenic fungi by producing at least nine different antibiotics. Here we investigated the closest relatives of Philanthus and Trachypus, the rare genus Philanthinus, for the presence of antennal gland reservoirs and symbiotic streptomycetes. Molecular analyses identified "Ca. Streptomyces philanthi" in reservoirs of Philanthinus quattuordecimpunctatus. Phylogenies based on the 16S rRNA gene suggest that P. quattuordecimpunctatus may have acquired "Ca. Streptomyces philanthi" by horizontal transfer from other beewolf species. In histological sections and three-dimensional reconstructions, the antennal gland reservoirs were found to occupy six antennal segments (as opposed to only five in Philanthus and Trachypus) and to be structurally less complex than those of the evolutionarily more derived genera of beewolves. The presence of "Ca. Streptomyces philanthi" in antennal glands of Philanthinus indicates that the symbiosis between beewolves and Streptomyces bacteria is much older than previously thought. It probably evolved along the branch leading to the monophyletic tribe Philanthini, as it seems to be confined to the genera Philanthus, Trachypus, and Philanthinus, which together comprise 172 described species of solitary wasps.

Chemical Analyses of Wasp-Associated Streptomyces Bacteria Reveal a Prolific Potential for Natural Products Discovery

Identifying new sources for small molecule discovery is necessary to help mitigate the continuous emergence of antibiotic-resistance in pathogenic microbes. Recent studies indicate that one potentially rich source of novel natural products is Actinobacterial symbionts associated with social and solitary Hymenoptera. Here we test this possibility by examining two species of solitary mud dauber wasps, Sceliphron caementarium and Chalybion californicum. We performed enrichment isolations from 33 wasps and obtained more than 200 isolates of Streptomyces Actinobacteria. Chemical analyses of 15 of these isolates identified 11 distinct and structurally diverse secondary metabolites, including a novel polyunsaturated and polyoxygenated macrocyclic lactam, which we name sceliphrolactam. By pairing the 15 Streptomyces strains against a collection of fungi and bacteria, we document their antifungal and antibacterial activity. The prevalence and anti-microbial properties of Actinobacteria associated with these two solitary wasp species suggest the potential role of these Streptomyces as antibiotic-producing symbionts, potentially helping defend their wasp hosts from pathogenic microbes. Finding phylogenetically diverse and chemically prolific Actinobacteria from solitary wasps suggests that insect-associated Actinobacteria can provide a valuable source of novel natural products of pharmaceutical interest.

Alpha–beta diversity in trap‐nesting wasps (Hymenoptera: Aculeata) in Southern Brazil

AbstractThis study was carried out at the Parque Municipal das Araucárias, in the municipality of Guarapuava, state of Paraná, southern Brazil. The aims of the present study were to access the spectrum of wasp species inhabiting trap‐nests in three habitats, to record their richness and diversity and elucidate the process responsible for their composition and abundance and to investigate if there is difference in their diversity between Brazilian tropical and subtropical regions. A total of 1097 nests, belonging to 21 species of solitary wasps, were collected. Of these, nine belonged to the family Vespidae (42.86%), six to Pompilidae (28.57%), four to Crabronidae (19.05%) and two to Sphecidae (9.52%). Crabronidae was the most abundant family in the samplings, with a total of 927 collected nests (84.3%). The environment that presented the greatest species diversity, richness and evenness was the grassland areas. Using the Bray–Curtis coefficient (beta diversity), the greatest similarity, in relation to species abundance, occurred between swamp and grasslands. In contrast, the araucaria forest was the habitat with the greatest dissimilarity, a result corroborated by the correspondence analysis.

Sublethal effect of brood parasitism on the grass‐carrying wasp Isodontia mexicana

Abstract 1. The nests of solitary, nest‐provisioning wasps (Sphecidae and Crabronidae) are commonly attacked by brood parasites, including flies of the families Phoridae and Sarcophagidae. Larvae of the flies commonly kill the wasp offspring directly or starve it by consuming prey provided by the adult female wasps.2. To determine whether brood parasitic flies can have a sublethal effect (i.e. reduced body size) on wasp offspring, nests of the wasp Isodontia mexicana were collected at two field sites in upstate New York, U.S.A. Nest diameter had no effect on the probability that a wasp cell would be inhabited by a brood parasite. Most offspring that developed in cells also containing phorids or sarcophagids managed to complete development and emerge as adults. Nevertheless, they had significantly smaller body size than conspecifics emerging from unparasitised cells in which the developing wasp did not have to compete for food (which in this species consists of tree crickets and katydids). Apparently, this is the first time that a sublethal effect of brood parasitism on offspring body size has been quantified for a solitary wasp species. Known effects of body size on the reproductive success of adult wasps suggest that sublethal consequences of the presence of brood parasites may have a significant effect on the fitness of adult I. mexicana.

Molecular Phylogeny of Vespidae (Hymenoptera) and the Evolution of Sociality in Wasps

The oriental Stenogastrinae is a group in which there is considerable interest as regards the study of evolution of sociality in wasps, because they show broad diversity in social behavior. Using cladistic analysis on morphological and behavioral data, they have been grouped together with the social Vespinae and Polistinae in the family of Vespidae. This is not without dispute, because several other morphological and behavioral characters separate Stenogastrinae from the other Vespidae subfamilies. DNA sequences were obtained from nuclear 28S ribosomal DNA and the mitochondrial 16S ribosomal DNA of twoApisspecies and nine social and three solitary wasp species of the family Vespidae. Solitary wasps of the family Braconidae and Pteromalidae were used as outgroups. Parsimony, distance, and maximum-likelihood methods of both mitochondrial and nuclear DNA did not support the conventional phylogenetic position of Stenogastrinae. In all phylogenetic reconstructions, the solitary Eumeninae were a sister taxon to the Polistinae + Vespinae cluster. The analyzed sequences provide strong evidence that sociality has independently evolved twice in the Vespidae.

EUSOCIALITY AND GENETIC VARIABILITY: A RE-EVALUATION.

Recently, much attention has focused on the patterning of intraspecific genetic variation among solitary, primitively eusocial, and advanced eusocial Hymenoptera. Berkelhamer (1983), after an analysis of electrophoretic data from 51 hymenopteran species, concludes that primitively eusocial species are less genetically variable than are either solitary or advanced eusocial species. She believes this pattern supports the idea that eusociality arose in species with relatively inbred populations, and she considers the implications of inbreeding for genetic models of the origin of hymenopteran eusociality. We have discovered two serious errors in Berkelhamer's analysis: 1) several species are assigned an incorrect social classification, and 2) her statistical comparisons of mean heterozygosity values (H) of solitary, primitively eusocial, and advanced eusocial groups fail to control for possible taxonomic biases in genetic variability. If these errors are corrected, a re-analysis of the same data yields results that differ markedly from those presented by Berkelhamer. In Table 2, Berkelhamer incorrectly classifies the four wasp species of the genus Polistes as advanced eusocial species. Polistes societies are universally classified by insect sociobiologists as primitively eusocial relative to the advanced eusocial species Berkelhamer considers: Polistes species exhibit all of the characteristics Berkelhamer herself (p. 543) views as diagnostic of primitive eusociality (i.e., relatively small nest size, little or no morphological caste differentiation, and behavioral domination of the workers by the queen; Evans, 1958; Evans and Eberhard, 1970; Wilson, 1971 p. 8; Spradbery, 1973; Akre, 1982). Conversely, the advanced eusocial wasp species, Vespula vulgaris, which displays large, sometimes perennial, colonies, pronounced morphological caste differentiation, and chemical queen control, is erroneously categorized as primitively eusocial. These errors have a large effect on Berkelhamer's results since the Polistes species have relatively high H values and the Vespula species has an H of 0.000. Berkelhamer's statistical analyses of the data she presents in Table 2 are vulnerable to taxonomic biases. She made pairwise comparisons of the 1H values of three groups: advanced eusocial species (N = 24; 18 ant, 2 bee, and 4 wasp species), primitively eusocial species (N = 9; 8 bee and 1 wasp species), and solitary species (N = 18; 10 bee, 7 wasp, and 1 sawfly species). Clearly, differences in H among these groups could reflect taxonomic differences, instead of social level differences, in genetic variability. For example, ants are disproportionately represented in the advanced eusocial group, and bees are overrepresented in the primitively eusocial group. If ants were more genetically variable than bees for reasons unrelated to differences in social level (e.g., because of differences in population structure or ecology), then one would erroneously conclude from a simple pairwise comparison that advanced eusocial species are more genetically variable than are primitively eusocial species. Indeed, we found that ft (0.045) of all the (advanced eusocial) ant species is significantly greater than ft (0.011) of the two advanced eusocial bee species (P = 0.05, two-tailed Mann Whitney test), a result that is consistent with a possible taxonomic bias. One simple way to reduce a potential taxonomic bias without a two-way analysis of variance procedure is to make statistical comparisons only within taxonomic groups. Since eusociality likely arose independently in ants, bees, and wasps (Wilson, 1971), we believe the latter procedure is especially well-suited for providing independent tests of a putative association between genetic variability and level of sociality. We have corrected Berkelhamer's classification errors, and, using the data she presents in Table 2, we have compared the ft values of solitary, primitively eusocial, and advanced eusocial species within bees and within aculeate wasps (no comparisons were made within ants since all ant species are advanced eusocial). Within the wasps, primitively eusocial species exhibit the highest H (0.062), a trend contrary to that reported by Berkelhamer, but this value is not significantly different from H (0.052) of solitary wasp species (P > 0.10, twotailed Mann Whitney test). The single advanced eusocial wasp species (Vespula vulgaris) has a reported H of 0.000, but meaningful statistical comparisons with the other two groups are not possible. Within bees, solitary species have a higher H (0.032) than do primitively eusocial bees (H = 0.013), but the difference is not significant (P > 0. 10, two-tailed Mann Whitney test). The two advanced eusocial bee species exhibit the lowest H (0.01 1) but, again, insufficient sample size prevents meaningful comparisons. We therefore find no evidence that primitively eusocial species tend to be less genetically variable than solitary species as Berkelhamer claims. We

5-Hydroxytryptamine content of some arthropod venoms and venom-containing parts

The venom or venom-containing parts of 30 species of arthropods from North and South America were examined for their content of 5-hydroxytryptamine (5-HT). The characteristic fluorescence of 5-HT was used in its identification and quantitative estimation. No 5-HT was detected in venom or telsons of 7 species of scorpions. Venoms of 5 spiders were found to contain 5-HT. No 5-HT was detected in the stinging apparatus of two species of ants and 3 species of solitary wasps. Relatively large amounts of 5-HT were found in the sting apparatus of all social wasps that were examined. Most 5-HT was found in those wasps known to produce very painful stings.