Chemical deception among ant social parasites

Deception is widespread throughout the animal kingdom and various deceptive strategies are exemplified by social parasites. These are species of ants, bees and wasps that have evolved to invade, survive and reproduce within a host colony of another social species. This is achieved principally by chemical deception that tricks the host workers into treating the invading parasite as their own kin. Achieving levels of acceptance into typically hostile host colonies requires an amazing level of decep- tion as social insects have evolved complex species- and colony-specific recognition systems. This allows the detection of for- eigners, both hetero- and con-specific. Therefore, social parasitic ants not only have to overcome the unique species recognition profiles that each ant species produces, but also the subtle variations in theses profiles which generate the colony-specific profiles We present data on the level of chemical similarity between social parasites and their hosts in four different systems and then discuss these data in the wider context with previous studies, especially in respect to using multivariate statistical methods when looking for differences in these systems.     

Architectural complexity of marine crustacean burrows: unusual helical trace fossils from the Miocene of Mallorca,Spain

Gibert, J.M. de, Mas, G. & Ekdale, A.A. 2012: Architectural complexity of marine crustacean burrows: unusual helical trace fossils from the Miocene of Mallorca, Spain. Lethaia, Vol. 45, pp. 574–585. Unusual helical trace fossils occur in Tortonian shelfal calcarenites in the island of Mallorca. Their morphology may be either simple (ichnogenus Gyrolithes) or, more commonly, consist of two concentric helical burrows (ichnogenus Lapispira). They bear a very characteristic pelleted lining and are associated and probably connected to Thalassinoides and Ophiomorpha burrow systems very abundant in the same unit. These features allow the interpretation that the tracemaker was a thalassinidean shrimp. The complex and compound nature of these trace fossils is comparable to that seen in other modern and fossil crustacean burrow systems, and it reflects the behavioural plasticity of the architects. □Trace fossils, ichnology, ichnofabrics, crustacean burrows, Miocene, shallow marine, Lapispira.     

Gall wasps and their parasitoids in cork oak fragmented forests

Abstract.  1. This paper explores the potential effects of host-plant fragmentation on cork oak gall wasp populations (Cynipidae, Hymenoptera) and on their predators, lethal inquilines, and parasitoids. To address this objective, galls were collected across a gradient of cork oak ( Quercus suber ) forest fragmentation in the East Pyrenees (Albera, Spain), and they were incubated to obtain the parasitism rates.
2. Two hypotheses were tested: (1) Host-plant fragmentation may induce a decline in gall wasp populations because of area and isolation effects on local extinction and dispersal; as a consequence of that, parasitoids may decline even more strongly in fragmented habitats than their prey. (2) Host-plant fragmentation may cause a decline in gall wasp parasitoid populations that, in turn, can lead to an ecological release in their prey populations.
3. Among the eight cork oak gall wasps sampled in the study area of Albera, the gall abundances of three species ( Callirhytis glandium , Callirhytis rufescens , and Andricus hispanicus ) were significantly related to forest fragmentation. The overall abundance of gall wasps was affected by a radius of ≈ 890 m surrounding landscape, presenting constant abundances with forest loss until forest cover is reduced at ≈ 40%; below that value the abundance increased rapidly. Three inquilines and 23 parasitoids species were recorded after gall incubation. In 25 cases, species of inquilines and parasitoids were newly recorded for the corresponding host in the Iberian peninsula.
4. Although the overall parasitism rate was high (1.1), it was uncorrelated with fragmentation and with overall cynipid abundance. These results indicate that host-plant fragmentation was correlated with higher abundance of gall wasps, whereas the parasitism rate could not explain this hyper-abundance in small forest fragments.     

Ultraviolet reflectance and cryptic sexual dichromatism in the ocellated lizard, Lacerta (Timon) lepida (Squamata: Lacertidae)

Ultraviolet (UV) colorations have garnered extensive theoretical and empirical treatment in recent years, although the majority of studies have concerned themselves with avian taxa. However, many lizards have acute visual systems with retinal photoreceptors that are sensitive to UV wavelengths, and also display UV-reflecting colour patches. In the present study, we used UV photography and full-spectrum reflectance spectrophotometry to describe intra- and intersexual colour variation in adult ocellated lizards Lacerta ( Timon ) lepida and to obtain evidence of UV-based ornamentation. We also investigated whether any colour traits correlate with morphological traits potentially related to individual quality. The results obtained show that the prominent eyespots and blue outer ventral scales (OVS) that ocellated lizards have on their flanks reflect strongly in the UV range and are best described as UV/blue in coloration. The eyespots of males are larger and cover a larger surface area than those of females. However, these differences can be entirely accounted for by sex differences in body size, with males being generally larger than females. We also found differences in the shape of reflectance curves from males and females, with the eyespots and blue OVS of males being more UV-shifted than those of females. Other body regions have extremely low UV reflectance and are not sexually dichromatic. Eyespot size and the total surface area covered by eyespots increases with body size in males but not in females, suggesting that they may be signalling an intrinsic individual characteristic such as body size or male fighting ability. We also discuss the alternative and non-exclusive hypothesis that eyespots may function in lizards of both sexes as protective markings against predators.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 766–780.