Probability of Intra- and Interspecific Encounters, and the Duration of Parental Care in Nicrophorus investigator (Coleoptera: Silphidae)

In burying beetles (Nicrophorus), male and female pairs bury small carcasses to supply their larvae with food. Both parents care for their larvae for several days and defend them against other burying beetles that try to usurp the carcass. Male defense is very effective in preventing take-overs by conspecifics, but ineffective against attacks by larger congeners. From information on four species of Nicrophorus, Scott (1998) suggested that this asymmetry affects the duration of male care; males care longer when the major competitors are conspecifics, and leave early if they are larger congeners. We performed a field study examining the phenology of N. investigator Zetterstedt and its sympatric congeners in Bielefeld, Germany. Because of its relatively low abundance, an N. investigator arriving at a carcass had a much higher chance to meet an individual of another species of burying beetle than to meet a conspecific, suggesting that intraspecific competition is less important than competition by congeners. Breeding experiments showed that male care in N. investigator was shorter than in the numerically dominant species N. vespilloides Herbst and N. vespillo (L.), supporting Scott' hypothesis. However, we cannot exclude that the differences in male care were caused by other factors that vary between species, as for example the speed of larval development. Also, the probability of encounter used to estimate the relative importance of intra- and interspecific conflicts only gives a rough estimate of the competitive situation because of differences in fighting ability between specie

Are isomeric alkenes used in species recognition among neo-tropical stingless bees (Melipona spp)

The majority of our understanding of the role of cuticular hydrocarbons (CHC) in recognition is based largely on temperate ant species and honey bees. The stingless bees remain relatively poorly studied, despite being the largest group of eusocial bees, comprising more than 400 species in some 60 genera. The Meliponini and Apini diverged between 80-130 Myr B.P. so the evolutionary trajectories that shaped the chemical communication systems in ants, honeybees and stingless bees may be very different. Therefore, the main aim of this study was to study if a unique species CHC signal existed in Neotropical stingless bees, as shown for many temperate species, and if so what compounds are involved. This was achieved by collecting CHC data from 24 colonies belonging to six species of Melipona from North-eastern Brazil and comparing this new data with all previously published CHC studies on Melipona. We found that each of the eleven Melipona species studied so far each produced a unique species CHC signal based around their alkene isomer production. A remarkable number of alkene isomers, up to 25 in M. asilvai, indicated the diversification of alkene positional isomers among the stingless bees. The only other group to have really diversified in alkene isomer production are the primitively eusocial Bumblebees (Bombus spp), which are the sister group of the stingless bees. Furthermore, among the eleven Neotropical Melipona species we could detect no effect of the environment on the proportion of alkane production as has been suggested for some other species

The Antiquity and Evolutionary History of Social Behavior in Bees

A long-standing controversy in bee social evolution concerns whether highly eusocial behavior has evolved once or twice within the corbiculate Apidae. Corbiculate bees include the highly eusocial honey bees and stingless bees, the primitively eusocial bumble bees, and the predominantly solitary or communal orchid bees. Here we use a model-based approach to reconstruct the evolutionary history of eusociality and date the antiquity of eusocial behavior in apid bees, using a recent molecular phylogeny of the Apidae. We conclude that eusociality evolved once in the common ancestor of the corbiculate Apidae, advanced eusociality evolved independently in the honey and stingless bees, and that eusociality was lost in the orchid bees. Fossil-calibrated divergence time estimates reveal that eusociality first evolved at least 87 Mya (78 to 95 Mya) in the corbiculates, much earlier than in other groups of bees with less complex social behavior. These results provide a robust new evolutionary framework for studies of the organization and genetic basis of social behavior in honey bees and their relatives

Mitochondrial DNA sequence data provides further evidence that the honeybees of Kangaroo Island, Australia are of hybrid origin

Morphological, multivariate and allozyme data show that the honeybee populations of Kangaroo Island, Australia, are more similar to Apis mellifera ligustica than A m mellifera. However, our sequence analysis of the ATPase 6, COIII, cytochrome b and ND2 mitochondrial genes shows a significant association, 100% according to bootstrap resampling, between the Kangaroo Island haplotype and A m mellifera. Therefore it is likely that the Kangaroo Island population was originally established from hybrids. We conclude that the ancestral populations of A m mellifera contained both the 'mellifera' haplotypes reported here, with complementary fixations in Tasmania and on Kangaroo Island. Since A m mellifera mtDNA haplotypes are shared between Australian honeybees classified as A m mellifera and A m ligustica, then the dichotomous nature of mtDNA lineages cannot be used to identify bees to subspecies in Australia

Two ancient mitochondrial alleles in Australian honeybees

Sequence information (363 bp) was obtained following polymerase chain reaction (PCR) amplification for portions of the ATPas 6 and COIII mitochondrial genes for 8 commercial and 2 feral honeybee hives. Only 2 alleles were found; these differed by 6 base substitutions, which implies that they diverged before honeybees colonized Europe

Psychobehavioral Effects of Hormonal Contraceptive Use

Although female use of hormonal contraceptives (HCs) has been associated with a variety of physical side effects, the psychological and behavioral side effects have received comparatively little attention until recently. Indeed, the long-term impact of HC use on human psychology has been vastly under-researched and has only recently become a focus for mainstream scholars. Women who use HCs report higher rates of depression, reduced sexual functioning, and higher interest in short-term sexual relationships compared to their naturally-cycling counterparts. Also, HC use may alter women's ability to attract a mate, as well as the mate retention behaviors in both users and their romantic partners. Some evidence even suggests that HC use alters mate choice and may negatively affect sexual satisfaction in parous women, with potential effects on future offspring. Interestingly, HCs have become a standard method of population control for captive nonhuman primates, opening up exciting avenues for potential comparative research. Here, the existing literature on the psychobehavioral effects of HCs in humans and nonhuman primates is reviewed and discussed. The potential resulting downstream consequences for the path of human evolution and recommendations for how future research could tease apart the underlying causes of these psychobehavioral effects of HC use are discussed, including suggestions for research involving nonhuman primates