Foraging in a risky environment: a comparison of Bennett's wallabies Macropus rufogriseus rufogriseus (Marsupialia: Macropodidae) and red‐bellied pademelons Thylogale billiardierii (Marsupialia: Macropodidae) in open habitats

Abstract This study aimed to establish whether red‐bellied pademelons (Thylogale billiardierii) and Bennett's wallabies (Macropus rufogriseus rufogriseus) alter their foraging distribution in open habitat, in response to food availability and distance to protective shelter, the latter used as a measure of predation risk. Scat counts were used as a measure of the presence or absence of these macropods over two plantations (Russell and Dunalley). These plantations differed in both their on‐site food and shelter characteristics (the presence or absence of windrows). Logistic regression indicated that at Russell, which had low food availability but the presence of on‐site shelter, probability of scats of both species increased with the percentage cover of both edible and inedible vegetation. The probability of both pademelon and wallaby scats decreased with increasing distance from windrows, but increased with increasing distance from forest at the plantation edge. Logistic regression indicated that at Dunalley, which had high food availability but no on‐site shelter, the probability of scats of both species increased with an increase in the percentage cover of edible vegetation. In relation to predation risk, however, the two species differed in their response. Pademelons exhibited a decrease in scat probability with increasing distance from the forest at the plantation edge, while wallabies showed an increase in scat probability with distance from the forest at the plantation edge. Results indicated some differences in antipredation strategies of the two species, which may be a function of differences in body size.     

Evolution of sexual dichromatism: contribution of carotenoid- versus melanin-based coloration

In birds, carotenoid-based plumage coloration is more dependent on physical condition and foraging abilities and less constrained developmentally than is melanin-based coloration. Thus, female mate choice for honest signals should result in more intense sexual selection on carotenoid- than on melanin-based plumage coloration. Using variation in sexual dimorphism as an indirect measure of the intensity of sexual selection, we tested the prediction mat variation in sexual dimorphism is driven more by change in carotenoid-based coloration between males and females dian by change in melanin-based coloration. Examination of historical changes in carotenoid- versus melanin-based pigmentation in 126 extant species of Cardueline finches supported this prediction. We found that carotenoid-derived coloration changed more frequendy among congeners dian melanin-based coloration. In both sexes, increase in carotenoid-based coloration score, but not in melanin-based coloration score, was strongly associated with increase in sexual dichromatism. In addition, sexual dimorphism in carotenoid-based coloration contributed more to overall dichromatism than dimorphism in melanin-based plumage. Our results supported die hypothesis that melanin-based and carotenoid-based coloration have fundamentally different signal content and suggest that combining melanin-based and carotenoid-based coloration in comparative analyses is not appropriate.     

A dated molecular phylogeny for the Chironomidae (Diptera)

We provide the first highly sampled phylogeny estimate for the dipteran family Chironomidae using molecular data from fragments of two ribosomal genes (18S and 28S), one nuclear protein‐coding gene (CAD), and one mitochondrial protein‐coding gene (COI), analysed using mixed‐model Bayesian and maximum likelihood inference methods. The most recently described subfamilies Chilenomyiinae and Usambaromyiinae proved elusive, and are unsampled. We confirm monophyly of all sampled subfamilies except Prodiamesinae, which contains Propsilocerus Kieffer, previously in Orthocladiinae. The semifamily Chironomoinae is confirmed only if Telmatogetoninae is included, which is closer to Brundin's original suggestion. Buchonomyiinae is excluded from Chironomoinae: it is a sister group to all remaining Chironomidae, conforming more to Murray and Ashe's argumentation. Semifamily Tanypodoinae is a grade and unsupported as monophyletic: the austral Aphroteniinae alone is sister to all Chironomidae (less Buchonomyiinae). Podonominae is weakly supported as the next sister group, in contrast to some estimates that place this subfamily as sister group to Tanypodinae alone. In Diamesinae, the southern African Harrisonini is confirmed as a member, but embedded within austral tribe Heptagiini, which is confirmed as sister to the undersampled Diamesini. Tribe Pentaneurini and ‘non‐Pentaneurini’ taxa are reciprocally monophyletic in Tanypodinae. Recent molecular findings concerning Podonominae are substantiated, with a monophyletic tribe Podonomini, Boreochlini forming a grade and Lasiodiamesa Kieffer placed as sister to all other Podonominae, but with uncertainty. In Orthocladiinae, a postulated two‐tribe system of Orthocladiini and Metriocnemini can be supported after exclusion of a Corynoneura group and a Brillia group, which is revealed as sister to Stictocladius Edwards. The marine Clunio Haliday and Thalassosmittia Strenzke & Remmert (given high rank in the past) are clearly embedded deep in Orthocladiinae. The finding of Shangomyia Sæther & Wang + Xyiaomyia Sæther & Wang as sister group to all other Chironominae justifies high rank, as their authors suggested. Pseudochironomini (untested by sampling shortfall) is sister to a monophyletic Tanytarsini (with a weakly supported inclusion of the enigmatic Nandeva Wiedenbrug, Reiss & Fittkau). The tribe Chironomini can be supported only by excluding Shangomyia + Xyiaomyia, and a postulated monophyletic clade comprising several taxa such as Microtendipes Kieffer, with six‐segmented larval antennae and alternate Lauterborn organs, that is sister group to Pseudochironomini + Tanytarsini. The tempo of diversification of the family, deduced by divergence time analysis (beast ), shows Permian origination with subfamily stem‐group origination from the mid–late Triassic to the early Cretaceous. Crown‐group origination ranged from Podonominae on a short stem originating in the mid Jurassic to long‐stemmed Aphroteninae from the late Cretaceous. Node dates allow inference of some vicariance via Gondwanan fragmentation, including certain nodes involving southern Africa.     

The life history and decline of the threatened Australian frog,Litoria raniformis

A popular idea amongst ecologists last century was that animals which exploit dynamic environments often display ‘fast’ life history strategies (high fecundity, rapid growth and maturation, and low or variable adult survival rates) relative to those which occupy more stable environments. Whilst the underlying theory has been discredited, the categorization remains of interest, because species with ‘fast’ life history traits are thought to be more robust to human‐induced environmental change than those with ‘slow’ life history traits. We examined the life history traits of the endangered Australian frog Litoria raniformis, to determine whether it displays ‘fast’ life history traits (like its sister species L. aurea and L. castanea), and to assess the role of these traits in the decline of this species. Mark‐recapture data confirmed that L. raniformis displays rapid growth and maturation. The data also suggest that L. raniformis displays relatively low adult survival rates. We propose that the ‘fast’ life history traits of this species are adaptive to metapopulation dynamics. In turn, we suggest that the rapid decline of L. raniformis may have resulted from metapopulation collapse, driven ultimately by habitat loss, degradation and fragmentation, and proximately by severe stochastic perturbations.