Road-associated mortality has been identified as having major ecological effects on small, fragmented and declining populations. Both the common brushtail possum (Trichosurus vulpecula) and common ringtail possum (Pseudocheirus peregrinus) appear to be in decline in some regions across their natural ranges. Urban populations may be an exception; however, little is known of their population ecology. This study investigates age trends in a subset of road-killed brushtail and ringtail possums collected along eight northern Sydney roads between March 2004 and March 2006. From a total of 591 recorded road-killed possums, 86 were collected for use in this study (36 brushtails, 50 ringtails). Age was estimated using tooth wear patterns on cleaned skulls. Both species showed trends associated with age, and younger possums of both species were more likely to be killed on roads than older animals. Male-biased dispersal of subadult possums is considered a major contributing factor to the over-representation of young brushtail possums in this road-kill sample.

Knowledge of the selective pressures favouring parental care can inform our understanding of the evolutionary origins and transitions of sociality in insects. Here, we report upon investigations designed to estimate the costs and benefits of parental care in the egg-guarding hibiscus harlequin bug Tectocoris diophthalmus (Heteroptera: Scutelleridae). We found that the presence of a guarding female had no effect on hatching success under benign laboratory conditions. In the wild, however, guarding decreased the likelihood of total clutch failure, and produced a fourfold greater egghatching rate relative to unguarded clutches. Females guarded against generalist invertebrate egg predators, including conspecific nymphs, but were ineffective against hymenopteran egg parasitoids. Females continued to feed during the guarding period and exhibited no signs of weight loss or increased mortality due to this behaviour. We did not observe the production of subsequent clutches in any experimental females; therefore, the lifetime fecundity costs of providing parental care in T. diophthalmus remain indeterminate. Overall, maternal egg guarding appears to function as a relatively low cost-low benefit strategy that increases hatching success by protecting against predationbut not parasitism.Ethology 120 (2014) 607-615

Most insects employ non‐caring strategies to safeguard their eggs and offspring from predation. Parental care behaviour is extremely rare in insects, but has been described in several insect groups and particularly in the Hemiptera. Given that such behaviour is considered an evolutionary precursor to more complex forms of insect sociality, investigating the dynamics of parental care may inform our understanding of social evolution. In this paper, we describe the oviposition and maternal care behaviour of the egg‐guarding cotton or hibiscus harlequin bug Tectocoris diophthalmus (Thunberg, 1783) in the field. We also report the results of experimental manipulations designed to test for egg discrimination mechanisms in this species. Our observations indicate that females lay about 100 eggs in a cylindrical cluster around a branch or leaf petiole. Maternal care is limited to egg straddling and defensive postures and behaviours. These were only displayed when walking invertebrate predators approached the egg clutch; mothers were observed to react to the presence of parasitoid wasps on their clutches. Protective behaviours are only displayed by guarding females and are possibly triggered by oviposition, but will cease permanently if females are separated from their clutch for more than a few minutes. We found no evidence for clutch discrimination, as females guarded their own clutch as readily as unrelated eggs until hatching. Egg guarding in this species may have been selected to enhance offspring survival in a high predation environment.