Summary: Kreysing et al. (2012)

Vertebrate retinae are diverse, but, in general, are specialised either to maximise the amount of light hitting the retina (increased number of rods) or to enhance visual acuity (increased number of cones). Kreysing et al. (2012) noted a different functional type of retinae in elephantnose fish (Gnathonemus petersii) that is optimised for neither purpose. They found that cone photoreceptors group together in "reflecting, photonic crystal-lined cups" and these act as macroreceptors. In contrast, they found that rod photoreceptors occur behind these reflector cups, not in them. Interestingly, this arrangement matches photoreceptor sensitivity and allows for detecting mixed-colour stimuli and the grouping of these photoreceptor cells results in insensitivity to spatial noise. These allow for a more reliable flight reaction, given the fish's habitat (dim and turbid).

Summary: Kessler et al. (2012)

The evolution of social systems has been largely influenced by kin selection. Within a social group, the ability to recognize paternal kin is important for minimizing inbreeding and loss of genetic diversity. Kessler et al. (2012) investigated vocal paternal kin recognition in the grey mouse lemur (Microcebus murinus), one of the first studies to do so. They analysed ultrasonic male courtship and alarm calls, and found that advertisement calls contain patrilineal signatures, which females use to assess relatedness of males. Alarm calls did not seem to contain these signatures. Kessler et al. (2012) conclude that paternal kin recognition is not reliant on brain size or social complexity, but could be the ancestral state from which more complex, kin-based sociality has arisen.

Summary: Foster et al. (2012)

Postmenopausal life span in humans has encouraged studies investigating the evolution prolonged post-reproductive life span in other animals. Two mechanisms are proposed: 1) increased longevity - evolutionary benefits accumulate only during the reproductive phase; 2) evolved adaptation - the post-reproductive life span increases individual "genetic" survival, resulting in increased inclusive fitness. Foster et al. (2012) used a Cox proportional hazards model (6) to study the influence of a mother killer whale’s (Orcinus orca) death on offspring survival. Neither sex disperses from the maternal group, so old mothers can maximise their inclusive fitness by increasing offspring survival and reproductive success. In addition, mothers should only help sons, as mating occurs outside the matriline. Foster et al. (2012) showed that old females assist male offspring. As reproductive success increases with male age, increased survival of sons increases the inclusive fitness of mothers. Mothers can assist with foraging or will provide support during agonistic encounters. Foster et al.'s (2012) results support the premise that a long post-reproductive life span is an evolved adaptation.

Summary: Hut & Scharff (1998)

Endoscopic equipment can be used to observe the behaviour of ground-dwelling animals inside their burrows. Hut & Scharff (1998) used a 205cm manoeuvrable fibre optic industrial endoscope attached to a video system to assess tunnel-blocking behaviour in European ground squirrels Spermophilus citellus. They found that, in 82% of cases, a tunnel block was found approximately 57 cm from the tunnel entrance. They suggest that ground squirrels are actively avoiding under-ground predation by blocking the tunnels with sand, and that they do this when both entering and leaving the burrow. Hut & Scharff (1998) suggest that these squirrels likely show a high tolerance to low oxygen (hypoxia) and high carbon dioxide (hypercapnia) conditions.

Summary: Blumstein et al. (2004)

Blumstein et al. (2004) investigated social hibernation in yellow-bellied marmots (Marmota flaviventris), as the species has a harem/polygynous social system, by monitoring emergence patterns from hibernation. Females share burrows and show home-range overlap in summer. They found that, as for 14 other species of the marmots, yellow-bellied marmots are social hibernators. They indicate that, although they hibernate socially, they might not accrue benefits of social thermoregulation. Blumstein et al. (2004) suggest that emergence times are occurring earlier in the year, consistent with global climate change models that suggest an influence of climate change on hibernation patterns in sub-alpine areas.

Summary: Callander et al. (2012)

 Fighting success in most males is determined by physical strength and the value of the resource over which males fight. Callander et al. (2012) looked at the how much fiddler crabs Uca annulipes valued a territory/burrow as a resource during the breeding season. During the mating season, burrows were deemed more valuable, as males escalated fights to maintain a territory for breeding and mating. In the non-breeding season, however, males did not fight as hard, even though burrows are still considered a valuable resource for access to food. Interestingly, although males with regenerated claws are weaker competitors than males with undamaged appendages, damaged males fought extra hard to avoid evictions during the breeding season and escalated fights more to maintain the resource. Callander et al. (2012) suggest that weaker males should fight harder when the resource is required for breeding.

Summary: Boyd (2012)

Boyd (2012) indicates that, although ecological models may be limited in their ability to predict various ecosystem responses, they are important for determining what drives ecosystem vulnerability in the face of disturbance. He provides a brief review of Mougi & Kondoh's (2012) network models. These models suggest that positive (mutualistic) and negative (agonistic) interactions play a role in ecosystem stability. He further suggests that ecological network models, while limiting, are important for describing ecosystem characteristics on a general level and for providing an indication of how these systems respond under stressful conditions. He further stresses that management decisions are likely to be driven by the status keystone species in ecological networks.