Biological control is one of the methods available for control of Aedes aegypti populations. We used experimental microcosms to evaluate the effects of actual predation and predation risk by dragonfly larvae (Odonata) on larval development, adult longevity, and adult size of Ae. aegypti. We used six treatments: control, removal, variable density cues (Cues VD), fixed density cues (Cues FD), variable density predator (Predator VD), and fixed density predator (Predator FD) (n = 5 each). Predator treatments received one dragonfly larva. Cue treatments were composed of crushed Ae. aegypti larvae released into the microcosm. For the FD treatments, we maintained a larval density of 200 individuals. The average mortality of Ae. aegypti larvae in the Predator VD treatment was used as the standard mortality for the other treatments. Mosquitoes from the Predator VD and Cues VD treatments developed faster, and adults were larger and had greater longevity compared to all other treatments, likely due to the higher food availability from larval density reduction. High larval density negatively affected larval developmental time, adult size, and longevity. Males were less sensitive to density-dependent effects. Results from this study suggest that the presence of predators may lead to the emergence of adult mosquitoes with greater fitness, causing an overall positive effect on Ae. aegypti population growth rates.

Fruit flies (Diptera: Tephritidae) are major pests worldwide. The sterile insect technique, where millions of flies are reared, sterilized by irradiation and then released, is one of the most successful and ecologically friendly methods of controlling populations of these pests. The mating behaviour of irradiated and non-irradiated flies has been compared in earlier studies, but there has been little attention paid to the anti-predator behaviour of mass-reared flies, especially with respect to wild flies. Tephritid flies perform a supination display to their jumping spider predators in order to deter attacks. In this study, we evaluated the possibility of using this display to determine the anti-predator capabilities of mass-reared irradiated, non-irradiated flies, and wild flies. We used an arena setup and observed bouts between jumping spiders (Phidippus audax Hentz) and male Mexican fruit flies (Anastrepha ludens Loew). We show that although all flies performed a supination display to their predator, wild flies were more likely to perform a display and were significantly more successful in avoiding attack than mass-reared flies. We suggest that this interaction can be used to develop a rapid realistic method of quality control in evaluating anti-predator abilities of mass-reared fruit flies.

The legendary kraken, a giant cephalopod that emerged from the depths to attack ships and devour the sailors is reincarnated here in a miniature version. We describe an oceanic island-dwelling octopus (Octopus sp.nov.) preying on a sea bird, the brown noddy (Anous stolidus) in the tropical West Atlantic. While poised on a tide pool rim the bird was quickly seized by one or two of the octopus's arms and dragged underwater, where the octopus was lying in ambush. We suggest that this prey type hunting occurs occasionally, even if rarely documented. Catching birds may have originated from ambushing mobile and relatively large animals such as Sally Lightfoot crabs (Grapsus grapsus), one prey of octopuses hunting in tide pools at oceanic islands in the tropical West Atlantic.

Previous studies have shown that the aphid species, Aphis fabae Scopoli and Megoura viciae Buckton, do not produce winged offspring in the presence of natural enemies, in contrast to results for the pea aphid (Acyrthosiphon pisum (Harris)) and the cotton aphid (Aphis gossypii Glover); but these studies did not involve exposing aphids directly to natural enemies. We exposed colonies of both A. fabae and M. viciae to foraging lacewing (Chrysoperla carnea (Stephens)) larvae and found that the predators did not induce winged morphs among offspring compared to unexposed controls. Colonies of A. fabae responded to an increase in aphid density with increasing winged morph production, while such response was not found for M. viciae. We suggest that different aphid species differ in their susceptibility to natural enemy attack, as well as in their sensitivity to contact.

Most regions of the world support moth species that use caves as diurnal roosts and/or as overwintering and mating sites. Although subterranean roosts are often also occupied by insectivorous bats, nothing is known about moth–bat interaction at these sites. The frequency of cohabitation and the dynamics of moth–bat interaction at roosts were examined during surveys at 30 known bat roosts in eastern Australia; 15 disused mines and 15 natural caves. Moths and bats cohabited in 20 roosts (67%); however, only two species of eared moths, Speiredonia spectans and S. mutabilis (Noctuidae), were observed. These large (wingspan up to 75 mm) species show a classic escape response to ultrasound. Moths used roosts occupied by bats with both frequency modulated (FM) (four species) and constant frequency (CF) (two species) echolocation calls. Signal frequencies of these bats had ranges of 23–25 and 44–71 kHz. Moths were absent from roosts occupied by high-frequency (>140 kHz) CF bats. Predator–prey interaction was assessed by studying a sub-sample of six roosts occupied by S. spectans and the horseshoe bat Rhinolophus megaphyllus. Speiredonia spectans and R. megaphyllus cohabited roosts throughout the year. Bats captured and consumed moths in these roosts. The numbers of moth wings on the floor of roosts were counted to assess rates of predation. Bats consumed 209 moths at the six roosts over a 12-month period, representing 19% of the moth population at the start of the study. The study establishes that moth–bat cohabitation of roosts is relatively common in eastern Australia and that bats do capture moths in these sites. Bat predation seems to be a significant source of mortality of moths that occupy subterranean roosts.