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1.
The display of female traits by males is widespread in the animal kingdom. In several species, this phenomenon has been shown to function adaptively as a male mating strategy to deceive sexual rivals (female mimicry). Freshly emerged males of the parasitic wasp Lariophagus distinguendus (Hymenoptera: Pteromalidae) are perceived by other males as if they were females because of a very similar composition of cuticular hydrocarbons which function as a sex pheromone in this species inducing courtship behaviour in males. Within 32 h, however, males deactivate the pheromone and are no longer courted by other males. In this paper, behavioural experiments were performed to test hypotheses on potential costs and benefits associated with the female odour in young males. We did not find any benefits, but demonstrated that young males were significantly more often outrivaled in male-male contests when competing with two older males for a female. Also, young males were significantly more often mounted in homosexual courtship events during these contests. Thus, display of female traits by males is not necessarily beneficial, and in fact, can be disadvantageous. We suggest that these costs have favoured the evolution of the pheromone deactivation mechanism in L. distinguendus males. The function of cuticular hydrocarbons as a female courtship pheromone in L. distinguendus might have evolved secondarily from a primary function relevant for both genders, and the deactivation of the signal in males might have caused a shift of specificity of the chemical signal from the species level to the sex level. 相似文献
2.
The data on the dynamics of population size and species composition of wasps from the families Pompilidae, Sphecidae, and Vespidae were obtained in the course of long-term studies carried out in successional pine forests of the Berezinskii Biosphere Reserve. The abundance and species diversity of wasps were significantly higher in a polewood forest (40 years) than in a young forest (20 years) and mature moss forest (70 years). In an overgrown ride in the moss pine forest, the composition of dominant wasp species remained relatively stable during the seven-year period of observations, although the number of species and their abundance varied significantly from year to year, depending on the weather. 相似文献
3.
Social wasps from temperate zones have clear annual colony cycles, and the young queens hibernate during winter. In the subtropics, the only previously reported evidence for the existence of “hibernation” is the facultative winter aggregations of females during harsh climate conditions. As in temperate-zone species analyzed so far, we show in this study that in the paper wasp, Polistes versicolor, a subtropical species, body size increases as an unfavorable season approaches. Our morphological studies indicate that larger females come from winter aggregations—that is, they are new queens. Multivariate analyses indicate that size is the only variable analyzed that shows a relationship to the differences. Given the absence of a harsh climate, we suggest that the occurrence of winter aggregations in tropical P. versicolor functions to allow some females to wait for better environmental conditions to start a new nest, rather than all being obliged to start a new nest as soon as they emerge. 相似文献
4.
Sexual dimorphism has been linked to parasitoid mating structure by several authors. In turn mating structure has an important
influence on predicted sex ratio optima. Here we test the relationship between sexual dimorphism and sex ratio using data
from 19 species of bethylid wasps. Using phylogenetically based comparative methods we confirm the findings of a previous
cross-species analysis that sex ratio (proportion of males) is strongly and negatively correlated with clutch size. Using
cross-species comparisons we show an additional positive correlation of sex ratio and relative male size, as predicted. The
relationship however is not significant when using phylogenetically based methods. The cross-species result is largely due
to differences between two bethylid sub-families: the Epyrinae have relatively large males and relatively high sex ratios,
whereas the Bethylinae have relatively small males and lower sex ratios. Our study illustrates the benefits and drawbacks
of using cross-species versus phylogenetically based comparisons.
Received: 13 May 1997 / Accepted after revision: 12 January 1998 相似文献
5.
Mark D. E. Fellowes Steve G. Compton James M. Cook 《Behavioral ecology and sociobiology》1999,46(2):95-102
The populations of many species are structured such that mating is not random and occurs between members of local patches.
When patches are founded by a single female and all matings occur between siblings, brothers may compete with each other for
matings with their sisters. This local mate competition (LMC) selects for a female-biased sex ratio, especially in species
where females have control over offspring sex, as in the parasitic Hymenoptera. Two factors are predicted to decrease the
degree of female bias: (1) an increase in the number of foundress females in the patch and (2) an increase in the fraction
of individuals mating after dispersal from the natal patch. Pollinating fig wasps are well known as classic examples of species
where all matings occur in the local patch. We studied non-pollinating fig wasps, which are more diverse than the pollinating
fig wasps and also provide natural experimental groups of species with different male morphologies that are linked to different
mating structures. In this group of wasps, species with wingless males mate in the local patch (i.e. the fig fruit) while
winged male species mate after dispersal. Species with both kinds of male have a mixture of local and non-local mating. Data
from 44 species show that sex ratios (defined as the proportion of males) are in accordance with theoretical predictions:
wingless male species<wing-dimorphic male species<winged male species. These results are also supported by a formal comparative
analysis that controls for phylogeny. The foundress number is difficult to estimate directly for non-pollinating fig wasps
but a robust indirect method leads to the prediction that foundress number, and hence sex ratio, should increase with the
proportion of patches occupied in a crop. This result is supported strongly across 19 species with wingless males, but not
across 8 species with winged males. The mean sex ratios for species with winged males are not significantly different from
0.5, and the absence of the correlation observed across species with wingless males may reflect weak selection to adjust the
sex ratio in species whose population mating structure tends not to be subdivided. The same relationship is also predicted
to occur within species if individual females adjust their sex ratios facultatively. This final prediction was not supported
by data from a wingless male species, a male wing-dimorphic species or a winged male species.
Received: 27 July 1998 / Received in revised form: 11 January 1999 / Accepted: 16 January 1999 相似文献
6.
Wasps robbing food from ants: a frequent behavior? 总被引:1,自引:0,他引:1
Food robbing, or cleptobiosis, has been well documented throughout the animal kingdom. For insects, intrafamilial food robbing
is known among ants, but social wasps (Vespidae; Polistinae) taking food from ants has, to the best of our knowledge, never
been reported. In this paper, we present two cases involving social wasps robbing food from ants associated with myrmecophytes.
(1) Polybioides tabida F. (Ropalidiini) rob pieces of prey from Tetraponera aethiops Smith (Formicidae; Pseudomyrmecinae) specifically associated with Barteria fistulosa Mast. (Passifloraceae). (2) Charterginus spp. (Epiponini) rob food bodies from myrmecophytic Cecropia (Cecropiaceae) exploited by their Azteca mutualists (Formicidae; Dolichoderinae) or by opportunistic ants (that also attack cleptobiotic wasps). We note here that
wasps gather food bodies (1) when ants are not yet active; (2) when ants are active, but avoiding any contact with them by
flying off when attacked; and (3) through the coordinated efforts of two to five wasps, wherein one of them prevents the ants
from leaving their nest, while the other wasps freely gather the food bodies. We suggest that these interactions are more
common than previously thought. 相似文献
7.
A simple model based on feedback mechanisms is developed to describe the dynamics of brood production and colony development
of primitively eusocial paper wasps. The presence of pupae and empty cells stimulate egg laying, which varies between a basic
rate and a physiological maximum. Newly hatched larvae are fed eggs, causing fluctuations in brood demography and forming
cohorts of offspring. The basic feedback mechanisms produce emergent colony-level properties such as synchronized development
of the brood and mature nest size. Results suggest that it is incorrect to imply colony decline from lack of nest growth,
and that production of waves of offspring can be interpreted as the inevitable result of these simple feedback mechanisms
rather than the solution to ultimate optimality criteria. Simulations using the parameters estimated in Polistes dominulus Christ are compared to studies of live wasps to test the validity of the model. Comparing simulated results with a perturbation
experiment in nature suggests that feedback relationships establish a system that is robust and resilient against severe disturbance.
Received: 20 January 1996/Accepted after revision: 27 April 1996 相似文献
8.
Foundresses of the social wasp Polistes biglumis were tested to see whether they were able to recognize alien eggs experimentally introduced into their own nests. Foundresses
removed alien conspecific reproductive-destined eggs while they accepted worker-destined eggs. The results indicate that social
wasps discriminate among eggs and that they discriminate against alien eggs destined to produce unrelated reproductives. P. biglumis is a strictly solitary founding species, with no reproductive competition within colonies; thus, brood discrimination abilities
could have evolved as a counteradaptation against intra- and inter-specific brood parasitism.
Received: 12 May 2000 / Revised: 15 July 2000 / Accepted 20 July 2000 相似文献
9.
In behavioral ecology it is generally assumed that behavior is adaptive. This assumption is tested here for sex ratio manipulation in response to host size in the parasitoid wasp Spalangia cameroni. Females produce a greater proportion of daughters on larger hosts. If this behavior is adaptive, it is not through a positive effect of host size on the fitness of daughters, as theory suggests and as found for other species. Females that developed on larger hosts were not more successful at drilling into hosts, were not more successful at interspecific competition for hosts, and did not have greater dispersal ability as measured by wing loading (weight/area of wing and thorax). The possibility that S. cameroni's sex ratio manipulation may be adaptive through a negative effect of host size on the fitness of sons cannot be ruled out. Relative to males from larger hosts, males from smaller hosts had lower wing loading and thus potentially greater dispersal ability. The actual effect of wing loading on fitness remains to be tested. 相似文献
10.
R. Cervo F. R. Dani C. Cotoneschi C. Scala I. Lotti J. E. Strassmann D. C. Queller S. Turillazzi 《Behavioral ecology and sociobiology》2008,62(8):1319-1331
A challenge for parasites is how to evade the sophisticated detection and rejection abilities of potential hosts. Many studies
have shown how insect social parasites overcome host recognition systems and successfully enter host colonies. However, once
a social parasite has successfully usurped an alien nest, its brood still face the challenge of avoiding host recognition.
How immature stages of parasites fool the hosts has been little studied in social insects, though this has been deeply investigated
in birds. We look at how larvae of the paper wasp obligate social parasite Polistes sulcifer fool their hosts. We focus on cuticular hydrocarbons (CHCs), which are keys for adult recognition, and use behavioral recognition
assays. Parasite larvae might camouflage themselves either by underproducing CHCs (odorless hypothesis) or by acquiring a
chemical profile that matches that of their hosts. GC/MS analyses show that parasite larvae do not have lower levels of CHCs
and that their CHCs profile is similar to the host larval profile but shows a reduced colony specificity. Behavioral tests
show that the hosts discriminate against alien conspecific larvae from different colonies but are more tolerant towards parasite
larvae. Our results demonstrate that parasite larvae have evolved a host larval profile, which overcomes the host colony recognition
system probably because of the lower proportion of branched compounds compared to host larvae. In some ways, this is a similar
hypothesis to the odorless hypothesis, but it assumes that the parasite larvae are covered by a chemical blend that is not
meaningful to the host. 相似文献