Worker Age, Ovary Development, and Temporal Polyethism in the Swarm-Founding Wasp Polybia occidentalis (Hymenoptera: Vespidae)

I measured oocyte sizes of Polybia occidentalis workers to assess whether ovary development corresponded with adult age or with individual variation in behavior. Workers exhibited temporal polyethism by first working inside the nest, then performing on-nest tasks, and later foraging and defending the nest. Individuals varied in their ages at first performance of each of these sets of behavioral acts. Ovary development corresponded strongly with adult age. Workers' ovaries declined quickly after an initial phase of partial development. The period of ovary decline overlapped with the age range at which most workers began performing tasks on the exterior nest surface. However, after accounting for age effects, individual behavioral differences (rate of temporal polyethism and performance of foraging and defense tasks) did not correspond with ovary development. These data suggest that ovary development had little or no effect on variation in task performance by P. occidentalis workers on the nest surface.     

Male Reproductive Behavior of the Social Wasp Polistes fascatus (Hymenoptera: Vespidae)

Populations of male Polistes fuscatus simultaneously exhibit two different mate-locating tactics. Some males defend territories in female nesting and hibernation sites. These males frequently do not occupy the same territory each day, and they drag their gasters over perches, which may function to apply a secretion to the perch. Another segment of the population patrols large overlapping areas in female foraging sites. In contrast to territorial males, patrolling males do not rub their gasters on perches, and males seen on more than one day are tenacious to one area. Males in both sites are aggressive to other males and attempt to copulate with females. A laboratory study indicates that large males have an advantage in male-male competition. The mean size of patrollers is smaller than that of territorial males, indicating that patrollers are competitively inferior males. Yet there is considerable size overlap of males between the two sites, suggesting that there is also overlap in the range of probability of mating success between the two sites.     

Molecular Phylogeny and Biogeography of the Genus Ilex L. (Aquifoliaceae)

The chloroplast atpB-rbcL spacer was sequenced for 115 speciesof Ilex and forNemopanthus mucronatus (Aquifoliaceae). In addition,rbcL sequences were obtained for 47 selected species. Takentogether with fossil records in the literature, the data indicatethat: (1) the lineage Ilex was already cosmopolitan long beforethe end of the Cretaceous. A relative test of the rate of nucleotidesubstitution indicates that extant species do not representthe entire lineage because of the extinction of its basal branches.The common ancestor of the extant species probably appearedat the upper Tertiary. (2) Several Asian/North American disjunctionsare observed, as well as North American/South American relationships.The directions of these relationships are yet to be determined.The African species Ilex mitis is closely related to Asian species.Ilex anomala (Hawaii and Tahiti) is related to American species.Ilex perado and Ilex canariensis (both in Macaronesia) havetotally different relationships, the former being related toEurasian species, while relationships of the latter remain obscure.(3) Gene trees substantially contradict the systematics of Loesener.Nemopanthus,closely related to Ilex amelanchier, is nested in the genusIlex. The family Aquifoliaceae is organized in four groups,each of them having a geographic or ecological peculiarity.Copyright 2000 Annals of Botany Company Aquifoliaceae, chloroplast DNA, fossil record, historical biogeography, Ilex (holly tree), molecular phylogeny.     

Field preferences of the Social Wasp Vespula germanica (Hymenoptera: Vespidae) for Protein-rich Baits

Food preferences displayed by foraging insects are important from a fundamental perspective and in pest control. We studied the preference of an invasive wasp, V. germanica, for protein foods in field conditions. Preferences were evaluated by placing baits in a paired design in different habitats and analyzing wasp visits, using a Bayesian approach to the Thurstone model. V. germanica workers display a clear rating of preferences, but were affected by the presence of competitors at the bait. These results contribute knowledge aimed at toxic baiting protocols for this wasp and suggest that food choice is a complex process subject to the influence of diverse factors. We emphasize the importance of on-site paired comparisons in preference studies to fully understand the drivers of food choice by insects.     

Scraping Sounds Produced by a Social Wasp (Asteloeca ujhelyii, Hymenoptera: Vespidae)

A distinct behavior performed by workers of the social wasp Asteloeca ujhelyii is described: guard waSPS, sitting outside of the nest around the entrance hole, scratch the nest envelope with their forelegs, thereby producing an audible ‘scraping sound’. Field observations revealed a relationship between the occurrence of the scraping behavior and the occurrences of waSPS entering and leaving the nest. The scraping was experimentally reproduced in the laboratory by moving a dissected wasp's leg parallel to the plane of the nest envelope. The resulting substrate‐borne vibrations propagate very well over a distance of a few centimeters. The amplitude of these vibrations depends on the velocity of the scraping movements. The possible role of the scraping behavior in the waSPS’ communication is discussed.     

Nutrient Dynamics of a Swarm-founding Social Wasp Species,Polybia occidentalis (Hymenoptera: Vespidae)

The kinds, rates of acquisition, inter-individual transfers, and intra-colonial movements of nutrients were ascertained for the advanced eusocial paper wasp Polybia occidentalis (Olivier). Foraging worker wasps (“foragers”) bring arthropod prey and nutritive liquids (“nectar”) to the nest, and these are usually transferred to nest workers (“receivers”) on the outer nest envelope. Arthropod prey items, which are brought intact to the nest, are malaxated by one or more receivers before being fed to larvae; malaxating adults retain a portion of the hemolymph for their own nourishment. Nectar is usually transferred (via adult-adult torphallaxis) from foragers to receivers on the nest envelope; some nectar is given to larvae, and all adults that imbibe it retain at least some for their own nourishment. Larval saliva of P. occidentalis contains glucose, protein, and free amino acids and so is highly nutritive; the nutrient content of the saliva closely resembles that of the saliva of other social wasp taxa. Adult wasps imbibe larval saliva, but very little is apparently transferred by those adults (via trophallaxis) to nestmates. Brood cannibalism was infrequent during this study. Adult worker and male wasps possess chymotrypsin-like and trypsin-like enzyme in their midguts and so are likely capable of protein digestion. The midgut proteases show an age-correlated variation in concentration. Pulp foragers are significantly smaller and lighter in weight than are receivers.     

Social Network Analysis of Male Dominance in the Paper Wasp Mischocyttarus mastigophorus (Hymenoptera: Vespidae)

Social aggression is a pervasive feature of insect societies. In eusocial Hymenoptera, aggression among females can affect task performance and competition over direct reproduction (egg laying); in most species males participate in social interactions relatively rarely. Males of the independent-founding paper wasp Mischocyttarus mastigophorus are exceptional: they are aggressive toward female nestmates, leading us to explore the function of this unusual behavior. We applied social network analyses to data on M. mastigophorus social aggression to quantify sex differences in giving and receiving social aggression. The network analyses supported the pattern of biased male aggression toward female nestmates; females are relatively rarely aggressive to males. We then asked whether male aggression toward females was biased by females’ relative ovary development. Males were more aggressive toward females with better-developed ovaries, opposite to patterns of aggression among females. Because food brought to the colonies is often monopolized by dominant females, we suggest that males direct aggression toward socially dominant females with better-developed ovaries to obtain food. The implications of biased male aggression for female task performance and physiology are unknown.

     

Antennal Drumming,Trophallaxis, and Colony Development in the Social Wasp Polistes fuscatus (Hymenoptera: Vespidae)

Parental care is an important component of social behavior in both vertebrates and invertebrates. Social wasps are a useful system for investigating the interplay between behaviors associated with the feeding of larvae by adults and their role in the evolution and maintenance of sociality. Females of the primitively eusocial wasp genus Polistes perform conspicuous vibratory behaviors closely associated with adult–larva feeding interactions. Prior research strongly indicates that these signals are directed toward the larvae, but their function(s) remain unclear. Existing hypotheses on the function(s) have posited releaser effects on larvae, either stimulating or inhibiting release of larval saliva, a nutrient‐rich glandular secretion attractive to adults. Polistes fuscatus queens perform antennal drumming (AD), a behavior in which they rapidly beat their antennae synchronously on the rims of the nest cells during the feeding of larvae. We used radiolabeled prey to show that adults extract juice from the prey, which they subsequently regurgitate to larvae immediately following each AD burst. We also show that no saliva is imbibed by the queen during the contact. These results are consistent with the inhibition hypothesis on the function of AD, but not the stimulation hypothesis. We further demonstrate that AD is first performed on nests when the oldest larvae reach the third instar, and that the third instar is the first to produce measurable volumes of larval saliva. Removal of third‐, fourth‐, and/or fifth‐instar larvae from single‐foundress, pre‐pupal‐stage colonies did not cause a reduction in the queen’s AD rates compared with controls, suggesting that later‐stage larvae do not maintain AD behavior via an immediate releaser effect. We propose instead that third‐instar larvae, possibly via chemical components of the salivary secretion itself, modulate the physiology of queens so as to indirectly cause the onset and maintenance of AD behavior.     

散白蚁属Reticulitermes分子系统发育与生物地理学研究进展

散白蚁属Reticulitermes隶属于等翅目鼻白蚁科Rhinotermitidae,是一类危害严重的重要社会性昆虫。文章回顾了近年来国内外散白蚁属系统发育和生物地理学研究进展,主要比较了传统方法和分子方法对散白蚁属系统发育的研究,包括对鼻白蚁科的进化关系研究,散白蚁属的分子系统发育现状,分子技术发展过程的总结。对散白蚁属的地理分布与其进化关系研究进行了阐述。线粒体、核基因标记和微卫星系统发育分析可以用于推测具有重要经济价值的散白蚁种类如北美散白蚁等的入侵路线和可能的入侵机制。文章最后展望了新兴测序技术、线粒体全基因组、转录组和宏基因组分析等可以用于散白蚁属系统发育分析。     

A Molecular Phylogeny of Warbling-Finches (Poospiza): Paraphyly in a Neotropical Emberizid Genus

We investigated the phylogenetic relationships of 12 species within a single genus of neotropical passerine (Poospiza) using 849 bp (283 codons) of the cytochrome b mitochondrial gene. We further explored evolutionary affinities of these taxa using sequence from an additional 47 thraupine (tanagers) and 7 emberizine (sparrows and buntings) genera, members of the predominantly New World family Emberizidae. Poospiza have traditionally been considered part of the emberizine radiation. However, our analyses suggest that members of this genus are more closely related to some thraupine lineages than they are to the other neotropical emberizine genera included in our study (Atlapetes, Embernagra, Melopyrrha, Phrygilus, Saltatricula, Tiaris). Although member taxa are closely related, the genus Poospiza appears to be paraphyletic with representatives of 6 thraupine genera (Cnemoscopus, Cypsnagra, Hemispingus, Nephelornis, Pyrrhocoma, Thylpopsis) interspersed among four well-supported Poospiza clades. The majority of species within this Poospiza–thraupine clade have geographic ranges that are exclusive to, or partially overlap with, the Andes Mountains. It is probable that these mountains have played an important role in driving cladogenesis within this group. Sequence divergence (transversions only; mean 4.7 ± 1.3%) within the clade suggests that much of this diversification occurred within the late Miocene and Pliocene, a period coincident with major orogenic activity in central-western South America.     

Reproductive Status of Females in the Eusocial Wasp Polistes ferreri Saussure (Hymenoptera: Vespidae)

In the subfamily Polistinae, caste dimorphism is not pronounced and differences among females are primarily physiological and behavioral. We investigated factors that indicate the reproductive status in females of Polistes ferreri Saussure. We analyzed females from nine colonies and evaluated morphometric parameters, ovarian development, occurrence of insemination, relative age, and cuticular chemical profile. The colony females showed three kinds of ovarian development: type A, filamentous ovarioles; type B, ovarioles containing partially developed oocytes; and type C, long and well-developed ovarioles containing two or more mature oocytes. The stepwise discriminant analysis of the cuticular chemical profile showed that it was possible to distinguish the three groups of females: workers 1, workers 2, and queens. However, the stepwise discriminant analysis of the morphological differences did not show significant differences among these groups. The queens were among the older females in the colony and were always inseminated, while the age of the workers varied according to the stage of colony development.     

Males Exhibit Novel Relationships of Dominance with Nest Departure in the Social Paper Wasp Mischocyttarus mastigophorus (Hymenoptera: Vespidae)

In many animal societies, an individual's opportunities to reproduce correspond to their position in a dominance hierarchy. In primitively eusocial paper wasps, female social dominance and direct reproduction are positively associated with taking food from nest mates, but both negatively correlate with foraging flights. Female paper wasps reproduce by laying eggs in their nest, while males reproduce by leaving the nest to copulate. Males of Mischocyttarus mastigophorus are unusual because they reside on their natal nests for prolonged periods, and males direct aggression towards female nestmates. Mischocyttarus mastigophorus males provide an opportunity to further analyse the relationships between dominance, nutrition and nest departure. We found males' rates of social aggression, food taking behaviour, and rates of nest departure were positively correlated. Furthermore, males that initiated aggression at younger ages also began flying earlier, and males engaged in all three behaviours at younger ages than females. Male social aggression may lead to nutrient acquisition, which enable males to depart from the nest. We hypothesise that male nest departure could be adaptive if it increases male mating opportunities. This could account for the positive relationship between dominance and nest departure for males.     

Age and Morphological Changes in the Epiponini Wasp Polybia paulista Von Ihering (Hymenoptera: Vespidae)

The division of labor is a central theme in the study of social insects. In bees and wasps, this activity is regulated by age polyethism. Important physiological and morphological changes have been widely studied in the polyethism of honeybee workers. In contrast, this is a relatively unexplored subject in social vespids. Our goal was to determine if there are detectable morphological changes in the body of the Epiponini wasp Polybia paulista Von Ihering or in certain glands in relation to age polyethism. We observed changes in the body weight, the salivary gland, and the mandibular gland that were associated with age, and our results suggest that social relationships and task performance are important to these changes. This contrasts with observations in Polistes and is different from the Apis mellifera Linnaeus age polyethism model.     

The Function of Male Dominance in the Eusocial Wasp, Mischocyttarus mastigophorus (Hymenoptera: Vespidae)

Males of a Neotropical eusocial wasp, Mischocyttarus mastigophorus , are dominant over their female nest mates. Mischocyttarus mastigophorus males behave aggressively toward females, while females rarely bite or chase males. Aggressive interactions between the sexes are behaviorally indistinguishable from dominance interactions among females. Males are long-lived as adults, and can reside on nests for periods of at least one month. Furthermore, males comprise a large proportion of post-emergence colony populations throughout much of the colony cycle. Males on the nest perform maintenance tasks at low rates, but contribute little other labor to their colonies. Males do not forage, but consume a disproportionate amount of the food (nectar and insect prey) collected by workers. Males in some colonies direct disproportionate amounts of aggression toward their queens, which may further contribute to males' food procurement. These data suggest that adult males represent a considerable energetic and labor cost to their colonies. I hypothesize that the dominance structure of M. mastigophorus directs food resources to adult males, with the function of increasing their longevity. Increased male longevity may be selectively advantageous in tropical species such as M. mastigophorus that found new colonies throughout much or all of the year. When females initiate new nests over much of the year, individual males' mating opportunities may be temporally distributed, favoring longer adult lifespans. Male dominance is predicted to occur in other populations of independent-founding Neotropical Polistinae with asynchronous colony foundation.     

A Molecular Phylogeny of the Aphidiinae (Hymenoptera: Braconidae)

Phylogenetic relationships within the Aphidiinae, and between this and other subfamilies of Braconidae (Hymenoptera), were investigated using sequence data from three genes: elongation factor-1α, cytochrome b, and the second expansion segment of the 28S ribosomal subunit. Variation in both protein-coding genes was characterized by a high level of homoplasy, but analysis of the expansion segment—robust over a range of alignment methods and parameters—resolved some of the older divergences. Parsimony analysis of the combined data suggests the following tribal relationships: (Ephedrini + (Praini + (Aphidiini + Trioxini))). In addition, the cyclostome subfamilies were found to form a clade separate from the Aphidiinae, but relationships between the Aphidiinae and the noncyclostome braconids could not be resolved. The inferred phylogeny also supported a secondary loss of internal pupation within the Praini and a polyphyletic origin of endoparasitism within the Braconidae.     

Taxonomic Review of the Genus Pararrhynchium Saussure (Hymenoptera: Vespidae: Eumeninae) from Korea

Korean Pararrhynchium is taxonomically reviewed, resulting in recognition of two species: P. paradoxum paradoxum and P. ornatum bifasciatulum. The latter is new to Korea. Reviewed taxonomic information on the two species is presented, with male characters of P. ornatum bifasciatum hitherto unknown. The past misidentification of P. ornatum in Korea is ascertained.     

Molecular Phylogeny of the Genus Paramesotriton (Caudata: Salamandridae)

To elucidate the phylogeny of the genus Paramesotriton (Caudata: Salamandridae), we investigated three mitochondrial DNA gene fragments (1207 bp in total) of cytochrome b, ND2, and ND4 for its six recognized species. The phylogenetic relationships within Paramesotriton were reconstructed by maximum parsimony (MP) and maximum likelihood (ML) methods. Phylogenetic trees (MP and ML trees) that were constructed from the combined data set of the three gene fragments indicated that all six species of Paramesotriton formed a monophyletic group, with P. caudopunctatus as basal to the other five species. This result suggests that P. fuzhongensis is a valid species in Paramesotriton.     

Molecular Phylogeny and Biogeography of Percocypris (Cyprinidae,Teleostei)

Fierce predatory freshwater fishes, the species of Percocypris (Cyprinidae, Teleostei) inhabit large rivers or lakes, and have a specific distribution pattern. Only a single species or subspecies occurs in each large-scale drainage basin of the Southeastern Tibetan Plateau. In this study, the molecular phylogenetic relationships for all but one of the described subspecies/species of Percocypris were investigated based on three mitochondrial genes (16S; COI; Cyt b) and one nuclear marker (Rag2). The results of Maximum Likelihood and Bayesian Inference analyses show that Percocypris is a strongly supported monophyletic group and that it is the sister group of Schizothorax. Combined with analyses of morphological characters, our results suggest that Percocypris needs to be reclassified, and we propose that six species be recognized, with corresponding distributions in five main drainages (including one lake). In addition, based on the results of the estimation of divergence times and ancestral drainages, we hypothesize that Percocypris likely originated in the early Miocene from a paleo-connected drainage system containing the contemporary main drainages of the Southeastern Tibetan Plateau. This study suggests that vicariance (due to the uplift of the Tibetan Plateau modifying the large-scale morphologies of drainage basins in the Southeastern Tibetan Plateau) has played an important role in the speciation of the genus. Furthermore, external morphological characters (such as the length of the fins) and an internal trait (the position of pterygiophore) appear to be correlated with different habitats in rivers and the lake.