Use of genetic,climatic, and microbiological data to inform reintroduction of a regionally extinct butterfly

Species reintroductions are increasingly used as means of mitigating biodiversity loss. Besides habitat quality at the site targeted for reintroduction, the choice of source population can be critical for success. The butterfly Melanargia russiae (Esper´s marbled white) was extirpated from Hungary over 100 years ago, and a reintroduction program has recently been approved. We used museum specimens of this butterfly, mitochondrial DNA data (mtDNA), endosymbiont screening, and climatic‐similarity analyses to determine which extant populations should be used for its reintroduction. The species displayed 2 main mtDNA lineages across its range: 1 restricted to Iberia and southern France (Iberian lineage) and another found throughout the rest of its range (Eurasian lineage). These 2 lineages possessed highly divergent wsp alleles of the bacterial endosymbiont Wolbachia. The century‐old Hungarian specimens represented an endemic haplotype belonging to the Eurasian lineage, differing by one mutation from the Balkan and eastern European populations. The Hungarian populations of M. russiae occurred in areas with a colder and drier climate relative to most sites with extant known populations. Our results suggest the populations used for reintroduction to Hungary should belong to the Eurasian lineage, preferably from eastern Ukraine (genetically close and living in areas with the highest climatic similarity). Materials stored in museum collections can provide unique opportunities to document historical genetic diversity and help direct conservation.     

The neglected scent: on the marking function of urine in Lemur catta

In ring-tailed lemurs (Lemur catta) urine deposition can be combined with two different tail configurations: (i) tail held up in an evident display (urinate tail-up, UT-up); (ii) tail slightly raised to avoid its impregnation with urine (urinate tail-down, UT-down). We used both signaller- and receiver-based approaches to search for functional differences between these two kinds of urine deposition. We predicted that UT-up might be a complex signal combining olfactory and visual cues. We carried out observations and scent tests on four captive groups of ring-tailed lemurs. Group members sniffed/licked UT-up scents more frequently than UT-down ones. Moreover, UT-up showed peak levels during the mating season whereas UT-down did not. These findings suggest that urine can play a role in intra-group reproductive communication. Lemurs more frequently performed UT-up in a few drops and UT-down in streams. Recognition experiments clearly showed that individuals can discriminate between urine of their own group and urine from a foreign group (a necessary prerequisite for the use of urine in inter-group communication). The possible function of UT-up in inter-troop communication was supported by the higher frequency of this pattern along a fence separating two of the study groups. Moreover, in the presence of a dummy, the frequency of UT-up increased significantly. In conclusion, UT-up is a complex signal with multiple characteristics. By using different sensory channels, UT-up provides different types of information (location and signaller quality) and contains multiple messages directed both at group-members and neighbouring groups....to conceal this letter, the Minister had resorted to the comprehensive and sagacious expedient of not attempting to conceal it at all (from the Purloined letter E. A. Poe, 1845)     

Prehibernating aggregations of Polistes dominulus: an occasion to study early dominance assessment in social insects

At a very early age several mammals establish a first dominance hierarchy, which often persists into adulthood. Social wasps offer an excellent opportunity to study such a phenomenon in insects. Indeed, foundresses of several paper wasps meet in clusters to hibernate from September to March. In spring, wasps found new associative nests where linear hierarchies occur. In the first phase of hibernation, clustering Polistes dominulus wasps show most of the social interactions occurring on the nest 6 months later. At the emergence from diapause, some females already show some behavioral and physiological traits typical of dominant individuals. Here, we investigated the significance of the interactions in the autumnal clusters. We demonstrated that in a given pair, it is more likely that the dominant wasp in autumn becomes the alpha female in spring after the nest foundation phase occurred. Moreover, we showed that dominant females in clusters have both larger body size and ovaries. As ovarian development mainly depends on the social context, our findings seem to indicate that social factors affect the tendency to dominate in aggregations. Furthermore, we suggest that some females may reinforce their physiological status by dominating in clusters, thus increasing the probability to become dominant in spring.     

Home economics in an oak gall: behavioural and chemical immune strategies against a fungal pathogen in Temnothorax ant nests

The Science of Nature - Orchids attach their pollinaria (cohesive masses of pollen) to specific body parts of flower visitors, but usually not to the hairy and scaly body parts of flower-visiting...     

The asymmetric scent: ringtailed lemurs (<Emphasis Type="Italic">Lemur catta</Emphasis>) have distinct chemical signatures in left and right brachial glands

Distinctive cues are predicted to evolve when the benefits obtained by the recognition process overcome its costs. When individual recognition is particularly beneficial for both senders and receivers, the expression of strongly distinctive signals is predicted to evolve. On the other hand, it could be predicted that each individual should show a very stable individual signature. In the same perspective, a great stability of the individual signatures could be expected. Lemur catta is the first non-human primate in which olfactory individual recognition has been demonstrated on the basis of the specialized brachial gland secretions. In this paper, I performed gas chromatograph analyses of right and left gland samples collected in two different periods (breeding and non-breeding seasons) from seven males. The aim was to verify if a diversification in such cues, already demonstrated at the inter-individual level, also occurs at the intra-individual level between left and right glands. I verified, by discriminant analysis and chemical distance comparisons, that each gland of each lemur has its particular signature that is maintained through time. Moreover, such diversification resulted so marked to make the overall intra-individual chemical differences similar to/as strong as the inter-individual ones. Since in rodents several odors from different glands may be integrated in individual recognition, I suggest that bilateral diversification in L. catta scents may offer an enhanced distinctiveness that could provide benefits in mate choice and social relationships.     

Timing matters when assessing dominance and chemical signatures in the paper wasp Polistes dominulus

A recent study (Izzo et al., Behav Ecol Sociobiol 64: 857–864, 2010) reported that cuticular hydrocarbons (CHCs) correlate with fertility, not dominance, in the paper wasp Polistes dominulus thus contradicting the results of recent investigations which concluded that social dominance is the main determinant for CHC signatures in this species. We suggest here that different forms of dominance in the pre-nesting and post-nesting phases caused the apparently contradictory results. Thus the assumption that dominance behaviour in the pre-nesting stage is synonymous with dominance after colony foundation is incorrect. We provide standardised definitions for forms of “dominance” observed in the P. dominulus life cycle to avoid apparent discrepancies in the future among studies dealing with the same topics in different annual stages.     

Almost royal: incomplete suppression of host worker ovarian development by a social parasite wasp

Insect social parasites, like other parasites, may benefit from inhibiting their host from reproducing (complete or partial parasitic castration) because they can then exploit more of the host’s resources for their own reproduction. In particular, social parasites that kill or expel the host queen need to prevent host workers from reproducing; this is a common worker response to the absence of their queen. Indeed, host workers would benefit from detecting the presence of the parasite and investing in direct and indirect fitness. Studying whether and how social parasites control host worker reproduction can provide information about the degree of integration of the parasite in the host colony and help identify factors regulating workers’ reproductive decisions in social insects. We investigated whether the paper wasp social parasite, Polistes sulcifer, suppresses Polistes dominula (host) worker reproduction as efficiently as the dominant host female does in queen-right colonies by comparing worker reproductive efforts in parasitized and non-parasitized (control) colonies. Our results show that 6 weeks after usurpation of their colony by the social parasite, parasitized workers (1) had more developed ovaries than control workers and (2) laid more eggs as soon as the opportunity arose. This reproductive readiness of parasitized workers was not apparent 2 weeks after colony usurpation. This suggests that P. dominula workers have evolved means to react to social parasitism, as occurs in some ants, and that the parasite has only limited control over host reproduction.     

The asymmetric scent: ringtailed lemurs (<Emphasis Type="Italic">Lemur catta</Emphasis>) have distinct chemical signatures in left and right brachial glands

Distinctive cues are predicted to evolve when the benefits obtained by the recognition process overcome its costs. When individual recognition is particularly beneficial for both senders and receivers, the expression of strongly distinctive signals is predicted to evolve. On the other hand, it could be predicted that each individual should show a very stable individual signature. In the same perspective, a great stability of the individual signatures could be expected. Lemur catta is the first non-human primate in which olfactory individual recognition has been demonstrated on the basis of the specialized brachial gland secretions. In this paper, I performed gas chromatograph analyses of right and left gland samples collected in two different periods (breeding and non-breeding seasons) from seven males. The aim was to verify if a diversification in such cues, already demonstrated at the inter-individual level, also occurs at the intra-individual level between left and right glands. I verified, by discriminant analysis and chemical distance comparisons, that each gland of each lemur has its particular signature that is maintained through time. Moreover, such diversification resulted so marked to make the overall intra-individual chemical differences similar to/as strong as the inter-individual ones. Since in rodents several odors from different glands may be integrated in individual recognition, I suggest that bilateral diversification in L. catta scents may offer an enhanced distinctiveness that could provide benefits in mate choice and social relationships.