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Habitat destruction and fragmentation increasingly bring humans into close proximity with wildlife, particularly in urban contexts. Animals respond to humans using nuanced anti-predator responses, especially escape, with responses influenced by behavioral and life history traits, the nature of the risk, and aspects of the surrounding environment. Although many studies examine associations between broad-scale habitat characteristics (i.e. habitat type) and escape response, few investigate the influence of fine-scale aspects of the local habitat within which escape occurs. We test the "habitat connectivity hypothesis," suggesting that given the higher cost of escape within less connected habitats (due to the lack of protective cover), woodland birds should delay escape (tolerate more risk) than when in more connected habitat. We analyze flight-initiation distances (FIDs) of five species of woodland birds in urban Melbourne, south-eastern Australia. A negative effect of habitat connectivity (the proportion of the escape route with shrubs/trees/perchable infrastructure) on distance fled was evident for all study species, suggesting a higher cost of escape associated with lower connectivity. FID did not vary with connectivity at the location at which escape was initiated (four species), apart from a positive effect of habitat connectivity on FID for Noisy Miner Manorina melanocephala. We provide some support for two predictions of the "habitat connectivity hypothesis" in at least some taxa, and conclude it warrants further investigation across a broader range of taxa inhabiting contrasting landscapes. Increasing habitat connectivity within urban landscapes may reduce escape stress experienced by urban birds. [ABSTRACT FROM AUTHOR]

Interactions between biocontrol agents of crop pests can lead to neutral, detrimental, or improved outcomes for pest control. We investigated the existence and the nature of the additive interactions between a parasitoid, Diadegma semiclausum (Hellén) (Hymenoptera: Ichneumonidae), and two hemipteran predators, Oechalia schellenbergii Guérin‐Méneville (Pentatomidae) and Nabis kinbergii Reuter (Nabidae), of the diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), under laboratory conditions. In the presence of the parasitoid, both O. schellenbergii and N. kinbergii increased predation by 56 and 66%, respectively. The escape response of the prey to avoid being parasitized (moving backwards and sometimes spinning down from the leaf on a silk thread, becoming less cryptic to the predators), may be at the basis of the enhanced predation by these predatory bugs; however, further studies are necessary to test this hypothesis. As the predators did not preferentially consume either parasitised or unparasitised larvae, coincidental intraguild predation should not affect this positive outcome in relation to DBM suppression. The findings highlight the potential utility of combining these natural enemies and may have important implications for the management of DBM in brassica crops in Australia and other multi‐species systems. [ABSTRACT FROM AUTHOR]

A predator–prey interaction occurs between the asterinid seastars Meridiastra calcar and Parvulastra exigua, which are sympatric on the shores of southeast Australia. These seastars are important as omnivorous predators/scavengers (M. calcar) and surface grazing herbivores (P. exigua). Meridiastra calcar inhabits the lower shore, whilst P. exigua occupies the mid to high shore and they can co-occur in the mid-intertidal zone. Parvulastra exigua exhibits a fleeing response when they encounter M. calcar. We investigated this response to determine the cues that elicit this behaviour. We also determined if M. calcar moves toward P. exigua. Physical contact with M. calcar resulted in an 8.6-fold increase in velocity of P. exigua compared to basal locomotion. Water conditioned by M. calcar (chemosensory cue only) also elicited an increase in velocity, but this was lower, a 3.5-fold increase. The escape trajectory of P. exigua was most linear, 180° away from the point of touch when contacted with M. calcar. In contrast, while touch with a sham stimulus elicited some movement, velocity was low, and the direction of movement was not linear away from the point of stimulation. Meridiastra calcar did not move toward P. exigua in choice experiments, and this was not altered if P. exigua had been damaged. Our results suggest that the escape response of P. exigua is elicited by a physical touch from M. calcar and that they detect chemosensory cues from this predator. Chemosensory cues emanating from M. calcar populations in the lower intertidal zone may influence the behaviour of P. exigua to remain higher on the shore. This first study of a predator–prey interaction in intertidal seastars suggests that this behaviour influences their distribution across the tidal gradient. [ABSTRACT FROM AUTHOR]

The aim of this study is to develop a better understanding of seabird foraging behaviour and the anti-predator behaviour of their prey. Studies of seabirds' foraging and prey-capture behaviour, as it relates to the evasive and escape behaviour of schooling fish, are sparse. Our study was carried out at One Tree Reef on the southern end of the Great Barrier Reef, Australia. A school of hardyheads Pranesus capricornensis sheltered in the shallows over the sand flats in front of the research station for 14 non-consecutive days. In that time, Lesser Crested Terns Thalasseus bengalensis were observed for 10 hours from above the surface in 37 foraging bouts and for 40 minutes from underwater in at least one foraging bout. In each foraging bout, a single tern dived into the school. We found that terns on average dived at a rate of 0.67 ± 0.35 dives/minute from 4-5 m above the surface. The depth range of dives was 43-58 cm. Therefore, fish within 58 cm of the surface were potentially accessible. The total length of the hardyheads was 10-12 cm, which is within the size range useable by terns. Fish used flash expansion to escape diving terns and formed a vacuole around birds as they slowly ascended to the surface. This escape manoeuvre was effective about 80% of the time. The fish that were caught did not respond to the escape movements of the fish above them and, therefore, were isolated. Fish also used the C-startle response to escape terns underwater and in mid-air. The anti-predator manoeuvres of hardyheads are similar to those observed among Clupea spp. (herrings and sardines) and Ammodytes spp. (sand eels) escaping sub-surface predators. Hardyheads and sardines react in the same way to gannets Morus spp. and terns that plunge dive directly to their prey, partially confirming the prediction that results for plunge-diving gannets are generalisable to other gannets and boobies (Sula spp.), terns and gulls (Larus spp.), tropicbirds (Phaethon spp.), pelicans (Pelecanus spp.), and kingfishers (Alcedinidae). [ABSTRACT FROM AUTHOR]

Wildlife discriminate between potential threats they encounter and may modulate their escape responses accordingly. Flight-initiation distances (FIDs), the distance at which an animal initiates escape to an approaching threat, can inform separation distances which minimise disturbance. However, FID data are currently lacking for many common human-related stimuli encountered by wildlife. Our aim was to elucidate avian responses to a common human stimulus, bicycles being ridden in parks. We compare FIDs in response to a fast bicycle, slow bicycle and a single walker for a range of Australian birds commonly found in parks. When all 57 species were pooled, bicycles did not evoke longer FIDs than walkers. Single species models revealed that bicycles evoked longer FIDs for four of 12 well-sampled species. The response towards bicycles was more intense (i.e., more likely to involve flying) than to walkers for two of ten species. [ABSTRACT FROM AUTHOR]

Ocean acidification (OA) driven by sea water uptake of anthropogenic atmospheric CO 2 has broad deleterious effects on marine species including modified behavioural interactions such as between predators and prey. Predatory sea stars are key species in many marine ecosystems and often elicit defensive responses in their prey. This study investigated the effect of elevated CO 2 on the escape response of the sea star Parvulastra exigua to its sea star predator Meridiastra calcar. In response to touch by M. calcar , P. exigua exhibits a distinct fleeing response. The escape response of P. exigua with respect to velocity and escape trajectory was investigated after both species were acclimated in OA conditions. At pH T 7.6 and 7.8 velocity and escape trajectory of the fleeing response of P. exigua did not differ from that seen in the ambient treatment. However, there was a delay in the time that P. exigua started to flee with the initiation time being 2.8 times slower (10 vs 28 s) at pH T 7.6. This delay may increase the vulnerability of P. exigua to predation by M. calcar and have ecological effects with respect to the role of this species as an algal grazer on rocky shores of southeast Australia where these sea star species co-occur. • This is the first study to examine the effect of OA on a prey species of seastar. • The escape response of the seastar Parvulastra exigua is delayed in response to OA. • The trajectory of escape away from the predator was not impacted by OA. [ABSTRACT FROM AUTHOR]

Abstract: A high natural mortality rate has been documented for the saucer scallop Amusium balloti, an Australian scallop found on sediment bottoms at 30–60 m deep, but little is known about the causes of mortality. We studied escape responses of A. balloti to five consumers common in the bycatch of the scallop fishery as a means of identifying potential predators. The scallop showed a negligible to weak response when touched with the sea star Pentaceraster regulus and the red portunid crab Portunus rubromarginatus. The response was similar to that observed when the scallop was touched with a plastic object. In contrast, A. balloti showed a consistent and vigorous swimming response to contact with the slipper lobster Thenus orientalis, the blue swimmer crab Portunus pelagicus and the coral crab Charybdis cruciata. This was not a generalized response to crustaceans, given the scallop''s weak response to the red portunid crab. This is the first report of a scallop that has a strong swimming escape response to contact with decapod crustacean predators. [Copyright &y& Elsevier]

Acid sulfate soils are a major problem in modified coastal floodplains and are thought to have substantial impacts on estuarine species. In New South Wales, Australia, acid sulfate soils occur in every estuary and are thought to impact important fisheries species, such as Eastern School Prawn (Metapenaeus macleayi). These fisheries have experienced declining productivity over the last ten years and increasing occurrence of catchment-derived stressors in estuaries contribute to this problem. We evaluated the effect of pH 4–7.5 on School Prawn survival at two salinities (27 and 14.5), pH 5, 6 and 7.5 on the predation escape response (PER) speed at two salinities (27 and 14.5), and pH 4 and 7.5 on respiration rates. While mortality appeared to be greater in the high salinity treatment, there was no significant relationship between proportional survival and pH for either salinity treatment. Respiration was significantly slower under acidic conditions and the average PER was almost twice as fast at pH 7.5 compared to pH 5 (p < 0.05), indicating prawns may fall prey to predation more easily in acidic conditions. These findings confirm the hypothesised impacts of acidic water on penaeid prawns. Given that the conditions simulated in these experiments reflect those encountered in estuaries, acidic runoff may be contributing to bottlenecks for estuarine species and impacting fisheries productivity. Image 1 • Higher mortality at salinity 27 compared to salinity 14.5 (across all pH levels). • Respiration was significantly slower under acidic conditions. • Average predation escape response was almost twice as fast at pH 7.5 compared to pH 5. • School Prawn have increased mortality and predation risk in acidic conditions. Low pH from acid sulfate soil runoff impacts School Prawn fisheries through reducing respiration rates, slowing predation escape responses and increasing mortality. [ABSTRACT FROM AUTHOR]