Insectivorous bats have influenced the development of antipredator behavior in moths, green lacewings, crickets, and mantids; until recently, such adaptations were unknown in katydids. Foliage-gleaning bats in Panama can use the female-attracting, airborne calling songs of nocturnal katydids to locate prey. They also feed heavily on these insects. Katydid species sympatric with these bats exhibit markedly reduced calling song duty cycles. Males supplement shortened songs with complex, species-specific tremulations that generate vibrations that are inaudible to bats but reach conspecific females through a shared plant substrate. Female katydids do not call audibly but are also preyed on in large numbers, perhaps as a result of moving toward calling males.

By analysis of feces collected from bats in the field, we determined that aquatic insects, particularly chironomid Diptera, made up the major portion of the diet of Myotis lucifugus at sites in southern Ontario, northern New York, and Nova Scotia. The diets of adult males reflected the available insect prey as sampled by a malaise trap, while those of lactating females included proportionally more caddis flies and moths than were present in the malaise trap samples. The diets of subadults of both sexes showed greater variation than those of adults, although chironomids and caddis flies were important components. While we observed the aforementioned pattern at sites in Nova Scotia, northern New York, and southern Ontario, the diets of adult M. lucifugus in northern Ontario were as variable as those of subadults from more southerly areas. We suggest that M. lucifugus is opportunistic in its feeding habits, and that the adults efficiently harvest s warms of aquatic insects, a trait not fully acquired by the young we sampled at the end of August.

Myopophyllum speciosum is a pseudophylline katydid (Tettigoniidae) from the neotropics that generates unusually high ultrasonic frequencies as the dominant carrier in its calling song. Male calls average only 148 ms duration and are given at long intervals: 8.7 s. Pairing is completed with vibrational signals, generated at closer range by body oscillation (tremulation). Two distinctive vibrational motor patterns, short and long, are produced by both sexes. Physical parameters of the sound and vibratory signals of this species are described. The relatively high‐Q carrier frequency (mean = 81 kHz) varies between males over a range of 20 kHz but does not predict a singer's body size. Short tremulations are much more intense than long as measured by acceleration. Descriptions of the songs of three other pseudophylline species with unusually high principal carriers (65–105 kHz) are also presented. Eavesdropping by predatory bats offers the most plausible selective explanation for the features of M. speciosum's signal system. This hypothesis is supported by the species' sexually dimorphic defensive spination: males, the sound‐signalling sex, have metafemoral spines of greater size and distinctive orientation. Evidence for eavesdropping and for alternative hypotheses is assessed. Other neotropical tettigoniids in rainforest understorey also employ elaborate vibratory signals (species of Choeroparnops, Schedocentrus, Docidocercus, Copiphora) and some show a trend to reduce or even to eliminate their use of airborne sound. Some rainforest tettigoniids may have replaced acoustic with vibrational signalling as a response to bat eavesdropping.

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Free-flying individual Lasiurus cinereus semotus were observed as they foraged near incandescent lights on the island of Kauai, Hawaii. Two types of vocalizations were recorded from the bats: an echolocation–hunting signal with peak frequency of 27.8 kHz and an agonistic social signal, emitted while the bats were in aggressive pursuit of one another, with a peak frequency of 9.6 kHz. The tendency to vocalize agonistically increased with increased numbers of bats in the foraging area and increased as the density of insects available to the hunting bats decreased. Our observations suggest that the bats may gather echolocation information from their social signals. The bats at the site foraged under most weather conditions, including fog, moderate rain, strong winds, and temperatures as low as 13 °C. Groups of up to eight animals were common, although bats hunted in airspaces that were vigorously defended against other individuals. Small flies and small moths (< 10 mm body length) were the most common insects available as prey, but larger moths (16–20 mm) made up the bulk of the bats' diet. Moths larger than 20 mm were available but not fed on by the bats. This unique study site provides a rare opportunity to compare both prey availability to prey consumption in a population of bats. Our results suggest that this bat, at least on a short-term basis, exhibits a high degree of selectivity in its foraging, a behaviour similar to the mainland subspecies.

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A thorough knowledge of food habits and feeding behavior is essential to appreciate the adaptive significance of different bat echolocation call types (Simmons et al. 1979, Neuweiler 1984. This paper describes prey selection, foraging behavior and echolocation in 12 species of phyllostomine bats (Phyllostomidae) from Barro Colorado Island, Panama (BCI). Little is known about the natural history of these bats, but they are onmivorous, feeding on insects, fruit, pollen, nectar and small vertebrates (Gardner 1977). Most species have long ears and hover, and are thought to glean prey from foliage and other substrates (Hill & Smith 1984). In addition, Trachops cirrhosus and Micronycteris megalotis, M. hirsuta, and Tonatia silvicola (Tuttle et al. 1985, Belwood & Morris, in press) use prey produced sounds (frog and insect calls, respectively) to locate food.All bats were caught in dense forest, not in clearings or in areas without trees. Fecal analysis (Table 1) and captive feedings show that M. megalotis, M. hirsuta, T. silvicola, T. bidens, Mimon crenulatum, Macrophyl~ macrophyllum, and !~ cirrhosus feed heavily on insects (and the latter also on vertebrates). M. nicefori and Phylloderma stenops eat fruit, and Chrotopterus auritus only vertebrates. Phyllostomus discolor and P. hastatUS feed on insects and fruit, and the latter also on small vertebrates. Orthoptera (katydids, roaches, crickets) that usually do not fly, but move along the ground or foliage (pers. obs.), dominated in the diets of wild caught T. bidens, T. silvicola, T. cirrhosus, M. megalotis, and M. hirsuta, indicating that they were probably gleaned from various substrates. This was confirmed in the lab, where !. silvicola, !. cirrhosus, and~. hirsuta gleaned and consumed prey from feeding perches, rather than in the air. These bats responded to and captured only calling (or otherwise sound-producing) prey. Live, uncaged, moving but silent insects were never approached, even when they were only a few cm from hungry bats. Large beetles (>10 mm body length (BL» followed in importance in the diets. Only M. crenulatum and M. macrophyllum fed on non-orthopteroid insects (beetles-«S rom BL», and moths (size unknown), respectively, which mayor may not have been gleaned. Eleven M. hirsuta and 27 M. megalotis roosts, containing the remains of lO,944 and l2,OSS insects, respectively, were found. Usually, day roosts were also used as feeding roosts, for months or years at a time, indicating that the bats foraged regularly in small familiar areas. OVer two years, the major prey eaten by the 6 g M. megalotis, by number, were: roaches (lO-lS mm

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