Aerial Prey Research Articles

Small Scale Habitat Preferences of Myotis daubentonii, Pipistrellus pipistrellus, and Potential Aerial Prey in an Upland River Valley

Distribution and abundance of two temperate-zone insectivorous bats, Daubenton's (Myotis daubentonii) and common pipistrelle (Pipistrellus pipistrellus), and their potential prey were studied along an altitudinal river gradient in relation to environmental variables including air temperature, wind speed, water surface state, and presence or absence of bank-side trees. Using a Latin square design at ten different habitat combination types, ultrasound recordings and insect sampling were carried out to quantify bat habitat preferences and potential prey abundance and classification. Myotis daubentonii and P. pipistrellus activity was significantly higher over smooth water river sections with trees on either or both banks while cluttered and rapid water sections were avoided. Conversely, insect abundance was not related to water surface condition or the presence or absence of bank-side trees. Nematoceran dipterans made up 98% of insect numbers, with small numbers of brachycerans and cyclorrhaphans. The most common insect families were Chironomidae and Ceratopogonidae. There was no correlation between bat activity and aerial insect activity, suggesting that aerial prey availability is not the sole driver of bat habitat choice. Bat and insect abundance were each correlated positively with night-time air temperature. No bat passes or flying insects were recorded at temperatures < 4°C. At 5°C, only M. daubentonii were observed foraging, and at 6°C there were more M. daubentonii present than any other bat species. No correlation was found between number of bat passes hr-1 and wind speed, moon visibility, moon phase, and percentage cloud cover. Rain did not affect M. daubentonii, but P. pipistrellus preferred to forage on dry nights. Bats were predicted to forage preferentially where aerial insect abundance was highest but this was found to not be case, and other aspects such as detection of prey against clutter may have an important role to play in habitat choice.

Nocturnal Risks-High Bat Activity in the Agricultural Landscape Indicates Potential Pesticide Exposure

Although agriculture dominates much of Europe’s landscape, there is virtually no information on foraging activity of bats in different crops. Additionally little is known about pesticide exposure of bats and related effects and there are currently no specific regulatory requirements to include bats in European Union pesticide risk assessments for the registration of these chemicals although other mammals are considered. To evaluate the potential pesticide exposure of bats, we studied bat diversity and activity as well as the availability of aerial prey insects in different crops and semi-natural habitats in south-western Germany in a landscape dominated by agriculture. In 300 accumulated sampling nights more than 24,000 bat call sequences were acoustically recorded and, in parallel, almost 110,000 insects of suitable prey sizes were sampled by light traps. A total of 14 bat species were recorded, among them the locally rare and for Germany critically endangered northern bat (Eptesicus nilssonii) and the barbastelle (Barbastella barbastellum), all of them also occurring over agricultural fields. In comparison to agricultural habitats, higher activity levels in forest sites were only found for Myotis species but not for species of the genera Pipistrellus, Eptesicus and Nyctalus. There were no significant differences in the availability of aerial nocturnal insects between forest, meadow and agricultural habitats. Comparing the different agricultural crops, significantly fewer bat call sequences and lower numbers of nocturnal insects were collected above the vineyards compared to orchards, cereal and vegetable fields. Highest activity levels of all bat species were recorded above agricultural fields situated next to forests. Given the high bat activity levels recorded at several agricultural sites, among them orchard and vegetable fields both known for their high pesticide inputs, and the availability of suitable prey insects, we conclude that pesticide exposure via ingestion of contaminated insect prey is possible. This potential risk is currently not considered in the European pesticide risk assessment scheme.

Responses of orb-weaving spider aggregations to spatiotemporal variation in lake-to-land subsidies at Lake Mývatn, Iceland

Tundra ecosystems are often unproductive, and peaks in resource availability are highly variable in space and time. Therefore, the success of organisms inhabiting these biomes likely depends on their ability to efficiently exploit heterogeneously distributed resources. We assessed how orb-weaving spider (Larinioides patagiatus) aggregations near Lake Mývatn, Iceland, respond to large midge (Diptera: Chironomidae) emergences that subsidize ecological communities in the surrounding landscape. The emergences occur for only a few weeks each summer, and the subsidy declines with distance from the lakeshore, producing large spatiotemporal variation in prey availability that might drive orb-weaver foraging behavior. We conducted three surveys during different phases of the summer emergence along a distance gradient to quantify variation in spider aggregation, web size, and habitat use in response to prey abundance. We found that aggregation size increased with the abundance of aerial prey, with the highest orb-weaver densities occurring at peak midge emergence. In contrast, changes in web size did not vary with midge abundance, but rather were determined by physical habitat structure. Our results illustrate how orb-weaver aggregations and web building can respond to spatiotemporal variation in resource subsidies across ecosystem boundaries.

The Hawk-Eyed Songbird: Retinal Morphology, Eye Shape, and Visual Fields of an Aerial Insectivore.

Swallows are a unique group of songbirds because they are active-pursuit predators that execute all aspects of hunting prey in flight: search, detection, pursuit, and capture. We show that swallows have evolved a visual system that is unlike that of any other studied songbird. Swallows have a bifoveate retina that provides sharp lateral and frontal vision, an unusually long eye that enhances spatial resolution, a large posterior blind area, and a narrow binocular field. We also show that swallows and diurnal raptors (hawks and falcons) have converged on a similar visual configuration but that, interestingly, predatory songbirds that ambush prey (flycatchers) have not converged on the same suite of traits. Despite the commonly held belief that predators rely on binocular vision, the temporal (frontally projecting) fovea present in swallows-but not present in other songbirds-is likely not involved in binocular vision. Instead, swallows have four nonoverlapping foveae in a 100° arc around the beak, which can improve the tracking of frontally located aerial prey that are engaging in evasive maneuvers. Overall, vision in pursuit predators reflects the complex sensory demands of hunting in the air at high speeds and emphasizes the importance of acute frontal vision in predators.

Visual Tracking: Hot Pursuit with Tiny Eyes

Flying insect predators intercept their aerial prey with deadly precision. New research reveals that a tiny robber fly, with a brain smaller than a pinhead, achieves this using the same visual mechanism that we ourselves employ to catch a passing ball.

Archerfish use their shooting technique to produce adaptive underwater jets

Archerfish are renowned for dislodging aerial prey using well-aimed shots of water. Recently it has been shown that these fish can shape their aerial jets by adjusting the dynamics of their mouth opening and closing. This allows the fish to adjust their jet to target distance so that they can forcefully hit prey over considerable distances. Here, we suggest that archerfish use the same technique to also actively control jets under water. Fired from close range, the underwater jets are powerful enough to lift up buried food particles, which the fish then can pick up. We trained fish so that we could monitor their mouth opening and closing maneuvers during underwater shooting and compare them with those employed in aerial shooting. Our analysis suggests that the fish use the same dynamic mechanism to produce aerial and underwater jets and that they employ the same basic technique to adjust their jets in both conditions. When food is buried in substrate that consists of large particles, the fish use a brief pulse, but they use a longer one when the substrate is more fine-grained. These findings extend the notion that archerfish can flexibly shape their jets to be appropriate in different contexts and suggest that archerfish shooting might have been shaped both by constraints in aerial and underwater shooting.

A revised and dated phylogeny of cobweb spiders (Araneae, Araneoidea, Theridiidae): A predatory Cretaceous lineage diversifying in the era of the ants (Hymenoptera, Formicidae).

Cobweb spiders (Theridiidae) are highly diverse from the perspective of species richness, morphological diversity, variety of web architecture, and behavioral repertoires. The family includes over 50% of social spiders, a behavioral rarity among the order, and members of the family are furthermore the subject of research on venom, silk biomechanics, kleptoparasitism and web building, among other traits. Theridiidae is one of the most abundant groups of spiders, and thus key insect predators in many different ecosystems and is among relatively few spider families that show high degree of myrmecophagy. Modern comparative studies on all these fronts are best buttressed on a phylogenetic foundation. Our goal here is to offer a revised, dated, phylogenetic hypothesis for the family by summarizing previously published data from multiple molecular and morphological studies through data-mining, and adding novel data from several genera. We also test the hypothesis that the origin and diversification of cobweb spiders coincides with that of ants on which many species specialize as prey. The new phylogeny is largely congruent with prior studies and current taxonomy and should provide a useful tool for theridiid classification and for comparative analyses. Nevertheless, we also highlight the limitations of currently available data-the state of the art in Theridiidae phylogenetics-offering weak support for most of the deeper nodes in the phylogeny. Thus the need is clear for modern phylogenomic approaches to obtain a more solid understanding, especially of relationships among subfamilies. We recover the monophyly of currently recognized theridiid subfamilies with the exception of some enigmatic 'pholcommatines' (Styposis, Phoroncidia) and putative 'hadrotarsines' (Audifia, Tekellina) whose placement is uncertain in our analyses. Theridiidae dates back some 100 mya to the Cretaceous, a period of diversification in flowering plants and many groups of insects, including ants. The origin of cobweb spiders, and hence the cobweb-a speciallized trap for pedestrian prey-coincides with a major diversification shift in ants. The family becomes abundant in fossil record 50-40 mya as ants also diversify and reach dominance and contemporary patterns of abundances of theridiids and ants show the same trends, with increasing relative abundance towards the equator and at lower altitudes. We find that among orbiculariae, lineages that specialize on ant prey are non-randomly clustered within Theridiidae. Given these findings we hypothesize that the origin of the gumfoot web was a stepping stone that facilitated the capture of ants and resulted in specialized myrmecophagy in a number of 'basal' theridiids. We also document a subsequent loss in myrmecophagy, and associated increase in speciation rates, as 'recent' theridiid groups evolve diverse web forms and many return to the capture of aerial prey.

Heavily loaded flight and limits to the maximum size of dragonflies (Anisoptera) and griffenflies (Meganisoptera)

An original hypothesis is presented that the maximum mass and size of living anisopteran dragonflies are constrained by a physiological performance limit: the wing muscle power required to permit reproductively successful males to carry heavier females in the so-called wheel position' in flight. It is proposed that the same limit cannot have applied to all fossil Odonatoptera. As the physiology of the giant Carboniferous griffenfly Namurotypus sippeli precludes flight in the wheel position, it did not need to carry any substantial load aside from exogenous aerial prey. Based on its thorax dimensions, it is argued that Namurotypus flew with a relatively low maximum specific muscle power output in comparison with living Anisoptera. The extinction of some families of large Mesozoic Odonatoptera may have been exacerbated by competition with smaller (stem-) Anisoptera that evolved higher specific power outputs and superior flight performance similar to living Anisoptera. To investigate the credibility of this flight-performance size-limit hypothesis and its consequences, an analysis of the scaling of the required flight power and available muscle power is presented using allometric relations. It is found that for living Anisoptera and fossil Odonatoptera, there are different limiting sizes, above which the required specific flight power would exceed the available muscle specific power. These limits are directly related to maximum load-carrying capacity and the atmospheric air density at the habitual altitude. It is suggested that the largest living species of Petaluridae, Petalura ingentissima, is close to the proposed Anisoptera size limit at current near-sea-level air density conditions.

White tail spots and tail-flicking behavior enhance foraging performance in the Hooded Warbler

Many species of insectivorous birds have contrasting plumage patches that are often displayed during foraging. Although such displays are widely hypothesized to flush potential prey and enhance foraging performance, experimental evidence that they function in this way was previously available only from redstarts (Myioborus spp.). I provide additional evidence from an experimental study of the Hooded Warbler (Setophaga citrina) in northwestern Pennsylvania, USA. Hooded Warblers regularly flick their tails while foraging, revealing large white spots on the outer tail feathers. I tested the function of the white tail spots with plumage manipulation experiments. At nests containing 5-day-old nestlings, the attending adults were captured and assigned to one of two treatment groups. For experimental birds, I temporarily darkened the white tail spots with a brown marking pen; for sham-darkened controls, I applied a comparable amount of ink to the dark inner rectrices. Experimental birds with darkened tails showed significantly reduced foraging performance compared with controls, and the decline in foraging performance was driven almost entirely by a decreased frequency of aerial prey attack. High-definition video recording at nests showed that plumage manipulation also altered the types of prey females delivered to nestlings; females with darkened tails delivered significantly fewer winged insects, and proportionally more insect larvae, than controls. However, the types of prey delivered by males were unaffected by plumage manipulation. Tail-flicking behavior codevelops with independent foraging in juveniles and is a significant positive predictor of juvenile foraging performance, even when the effects of juvenile age and activity are controlled statistically. Collectively, these results provide strong support for the hypothesis that white tail spots and tail-flicking behavior of Hooded Warblers function to flush visually oriented winged prey and enhance foraging performance. They also raise questions about sexual dimorphism in the tail pattern and its relationship to possible sex differences in foraging strategies.

Visual search in hunting archerfish shares all hallmarks of human performance

Archerfish are renowned for shooting down aerial prey with water jets, but nothing is known about how they spot prey items in their richly structured mangrove habitats. We trained archerfish to stably assign the categories 'target' and 'background' to objects solely on the basis of non-motion cues. Unlike many other hunters, archerfish are able to discriminate a target from its background in the complete absence of either self-motion or relative motion parallax cues and without using stored information about the structure of the background. This allowed us to perform matched tests to compare the ways fish and humans scan stationary visual scenes. In humans, visual search is seen as a doorway to cortical mechanisms of how attention is allocated. Fish lack a cortex and we therefore wondered whether archerfish would differ from humans in how they scan a stationary visual scene. Our matched tests failed to disclose any differences in the dependence of response time distributions, a most sensitive indicator of the search mechanism, on number and complexity of background objects. Median and range of response times depended linearly on the number of background objects and the corresponding effective processing time per item increased similarly - approximately fourfold - in both humans and fish when the task was harder. Archerfish, like humans, also systematically scanned the scenery, starting with the closest object. Taken together, benchmark visual search tasks failed to disclose any difference between archerfish - who lack a cortex - and humans.

The miniature dipteran killer fly Coenosia attenuata exhibits adaptable aerial prey capture strategies.

Event Abstract Back to Event The miniature dipteran killer fly Coenosia attenuata exhibits adaptable aerial prey capture strategies. Trevor J. Wardill1*, Paloma T. Gonzalez-Bellido1*, Gervasio Tapia2, Hanchuan Peng3, 4 and Robert M. Olberg5 1 Marine Biological Laboratory, Program in Sensory Physiology and Behavior, United States 2 Instituto Andaluz de Investigación y Formación Agraria (IFAPA), Centro IFAPA La Mojonera, Spain 3 Howard Hughes Medical Institute, Janelia Farm Research Campus, United States 4 Allen Institute for Brain Science, United States 5 Union College, Department of Biology, United States Catching insects on the wing requires visual speed, acuity and body maneuverability. This situation is exemplified by dragonflies, which exhibit a predatory behavior and sport the largest of all insect eyes. However, miniature killer flies (Coenosia species, 4 mm body length) also catch targets midflight. How do miniature killer flies accommodate the limits of a small compound eye and maximize the probability of prey capture? To answer this question we recorded, with calibrated dual high-speed video cameras, the predatory behavior of Coenosia attenuata and Coenosia tigrina in the wild (greenhouses) and in captivity (glass enclosure). We used natural (Drosophila sp.) and artificial (plastic bead on fishing line) targets to elicit the attack and reconstructed the prey and predator trajectories in 3D. Our results show that killer flies take off after items three times their own body size, indicating that they do not know the absolute size of the potential prey prior to the flight. Because we found that killer flies contrast and pursue prey against cluttered backgrounds in all directions, we expected them to employ classical pursuit. However, the flight trajectories obtained in the wild show that after takeoff, the killer fly path points towards the future location of its prey i.e. interception. More importantly, and unlike dragonflies and hoverflies, we found that killer flies adapt their strategy, switching between open and closed loop, interception, classical pursuit and gleaning. For example, killer flies are not known to employ gleaning in the wild, but this is the most common predatory strategy in small enclosed spaces. In summary, we show that Coenosia species are successful miniature predators with a vast and complex behavioral repertoire that rivals those of insects with much larger brains. Our future work will expand this line of work, to build a model that predicts the behavior. The killer fly statistics gathered (see killer facts box) will be employed to investigate the neural computations that allow the fast switches between the different attack strategies here reported. Figure 1 Keywords: Predatory Behavior, High-Speed Video, interception, 3D Trajectory, Gleaning Conference: International Conference on Invertebrate Vision, Fjälkinge, Sweden, 1 Aug - 8 Aug, 2013. Presentation Type: Oral presentation preferred Topic: The visual control of flight and locomotion Citation: Wardill TJ, Gonzalez-Bellido PT, Tapia G, Peng H and Olberg RM (2019). The miniature dipteran killer fly Coenosia attenuata exhibits adaptable aerial prey capture strategies.. Front. Physiol. Conference Abstract: International Conference on Invertebrate Vision. doi: 10.3389/conf.fphys.2013.25.00057 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 25 Feb 2013; Published Online: 09 Dec 2019. * Correspondence: Dr. Trevor J Wardill, Marine Biological Laboratory, Program in Sensory Physiology and Behavior, Woods Hole, MA, 02543, United States, twardill@umn.edu Dr. Paloma T Gonzalez-Bellido, Marine Biological Laboratory, Program in Sensory Physiology and Behavior, Woods Hole, MA, 02543, United States, paloma@mbl.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Trevor J Wardill Paloma T Gonzalez-Bellido Gervasio Tapia Hanchuan Peng Robert M Olberg Google Trevor J Wardill Paloma T Gonzalez-Bellido Gervasio Tapia Hanchuan Peng Robert M Olberg Google Scholar Trevor J Wardill Paloma T Gonzalez-Bellido Gervasio Tapia Hanchuan Peng Robert M Olberg PubMed Trevor J Wardill Paloma T Gonzalez-Bellido Gervasio Tapia Hanchuan Peng Robert M Olberg Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Contributions of detrital subsidies to aboveground spiders during secondary succession, revealed by radiocarbon and stable isotope signatures

Prey subsidies originating from detritus add nutrients and energy to arboreal communities. Measurement of this subsidy is required in the understanding of how food web dynamics respond to changes in surrounding environments. Shrub spiders are one of the key predators involved in food web coupling. We evaluate the effects of potential changes in prey availabilities during secondary succession on the contribution of subsidy from detrital food webs to shrub spiders and how different spider feeding guilds used the subsidy of prey from detrital food webs. We measured the relative importance of the subsidy for the spider feeding guilds, using the ratios of stable isotopes of C (δ(13)C), and N (δ(15)N) and C isotope discrimination (Δ(14)C). Diet age was calculated from Δ(14)C values, because old diet ages of spiders indicate that the spiders consume prey from detrital food sources. Dominant aerial prey (Diptera) had a distinctively old diet age compared with arboreal prey, which indicates that aerial prey were subsidized from detrital food webs. Sit-and-wait spiders tended to have an older diet age than active hunting spiders, which indicates that sit-and-wait spiders depended more on subsidies. Diet age varied only slightly for spiders in stands of different ages, indicating that rates at which spiders use grazing and detrital prey are probably determined more by foraging strategies and not by stand age. A dominance of sit-and-wait predators will lead to higher detrital subsidy inputs in shrub habitats. This study highlights the effect of shrub spider community structure (feeding guild composition) on the volume of the subsidy received from the detrital food web.

Flagship bird species habitat management supports the presence of ground-nesting aculeate hymenopterans

Burrowing birds, such as sand martins (Riparia riparia), are tightly bound to resource patches narrowly defined by soil penetrability, clay content, low incidence of parasites, and sufficient amount of aerial prey. Such habitat patches are limited both in number and quality, and their management is expected to affect not only the target flagship species, but also the non-target species represented by solitary ground-nesting aculeate hymenopterans utilizing the same habitat patches. The efficiency of sand martin habitat restoration at 23 localities was evaluated. Since most of the successful efforts resulted in a decrease of soil penetration resistance, whether the observed penetration resistance decrease had an effect on non-target aculeate hymenopterans utilizing vertical or near-vertical slopes was studied. To assess this, penetration resistance and soil granulometric characteristics were measured at 39 randomly selected vertical slopes, and the density of ground-nesting aculeate hymenopterans was evaluated. Ground-nesting aculeate hymenopterans were found to avoid slopes containing only soil strata with high penetration resistance, or with high gravel content. The burrow density in slopes with regular (bi)annual management was similar to the burrow density in slopes with medium to low penetrability but with less frequent management efforts. Removal of the hard-packed crust resulted in the return of both sand martins and aculeate hymenopterans in the respective slopes. Flagship bird species habitat management was found to support not only the the target burrowing bird, but also the non-target ground-nesting aculeate hymenopteran species.

Food Habits of Two Fork-tailed Swifts in Venezuela

The aerial arthropod prey of Neotropical Palm Swifts (Tachornis squamata) and Lesser Swallow-tailed Swifts (Panyptila cayennensis) in Venezuela included seven Orders and 60 families of insects plus spiders and mites. Diptera were the most numerous prey (>50%) taken by both swifts. Prey size ranged from 0.5 to 7.9 mm and averaged 2.43 and 2.77 mm, respectively. Both prey type and foraging habitat differences of these swifts could be interpreted as mechanisms for resource partitioning.

Intraspecific kleptoparasitism and counter-tactics in the archerfish (Toxotes chatareus)

The mechanics of the archerfish’s remarkable ability to spit down aerial prey is well studied. Relatively unknown, however, are the social consequences of this hunting method. To explore how physical factors and behavioural choices affect the use and success of intraspecific kleptoparasitism in socially foraging archerfish, 10 tagged, juvenile archerfish (Toxotes chatareus) were presented in groups of 3, 5, and 7 with single crickets of 3 sizes overhanging the water by either 15 or 30 cm. Video review revealed all spits, jumps, attempted thefts, and consumptions. Kleptoparasitism attempts were common, resulting in a 43.6% loss rate to the fish that successfully brought down the prey. Group size affected the probability of kleptoparasitism asymptotically: loss rate increased as group size increased from 3 to 5 members, but with no further increase at 7 members. As observed with other kleptoparasitic species, the rate and success of kleptoparasitism increased with both prey size and prey height (analogous to handling time). Several counter-kleptoparasitism behaviours were observed, including jumping to grab prey directly, aggression, spitting technique, and positioning.

Systematics of the Spider Family Deinopidae with a Revision of the Genus Menneus

The enigmatic and rare spiders of the family Deinopidae are known for their extremely large ocelli and their unique habit of casting their small cribellate webs over nocturnal pedestrian or aerial prey. Although the monophyly of the family has not been controversial, deinopid descriptive systematics has been neglected since the original species descriptions. The first goal of this monograph is to test the monophyly of Deinopidae and its genera and thus to establish a phylogenetically informed taxonomy of the species. We provide the first phylogeny of this family on the basis of 53 morphological and 3 behavioral characters scored for 17 deinopid species and 2 outgroups. Extant deinopid spiders belong to two genera: the larger pantropical Deinopis MacLeay, 1839, diagnosed by the extreme size of their posterior median eyes, and the smaller Menneus Simon, 1876, of the Old World (sub)tropics with normally sized eyes. Avella Pickard-Cambridge, 1877, and Avellopsis Purcell, 1904, are junior synonyms of Menneus as their type species are nested throughout Menneus phylogeny. The second goal is to revise the non-Deinopis species of Deinopidae. Here, we recognize, diagnose, illustrate, describe, and phylogenetically place the 14 known Menneus species. Africa currently has six species: Menneus camelus Pocock, 1902, from South Africa; M. capensis (Purcell, 1904) new combination from Western Cape, South Africa; M. darwini new species from Tanzania; M. dromedarius Purcell, 1904 (removed from synonymy of M. camelus), from South Africa and Madagascar; M. samperi new species from Kenya, Tanzania, and Uganda; and M. tetragnathoides Simon, 1876 (M. affinis Tullgren, 1910 new synonym), from Angola, Malawi, and Tanzania. Australasia currently has eight species: M. aussie new species from eastern Australia and New Caledonia; M. bituberculatus new species from Queensland and Indonesian West Papua; M. superciliosus (Thorell, 1881) from eastern Australia; M. nemesio new species from New South Wales; M. neocaledonicus (Simon, 1889) from New Caledonia, M. quasimodo new species from Western Australia; M. trinodosus Rainbow, 1920 (Deinopis insularis Rainbow, 1920, new synonym), from Queensland and New South Wales; and M. wa, new species, from Western Australia. We propose Avella angulata L. Koch, 1878, Avella despiciens O. P.-Cambridge, 1877, and Avella unifasciata L. Koch, 1878, as nomina dubia. Paleomicromenneus lebanensis Penney, 2003, the earliest known fossil, is similar to Menneus. Menneus is phylogenetically sister to Deinopis, and within Menneus we recover a grade of Australasian species that includes the African M. capensis, followed by a distal clade of African species with peculiar asymmetric somatic morphology.

Beam-width control of echolocation pulses in Japanese CF-FM bats (Rhinolophus ferrumequinum nippon) during aerial prey hunting.

Beam-width control of echolocation pulses in Japanese CF-FM bats (Rhinolophus ferrumequinum nippon) during aerial prey hunting.

Food Composition of the Endemic Plain SwiftApus unicolorin the Canary Islands (Macaronesia)

As a first step to investigate the foraging ecology of the Plain Swift Apus unicolora the Canary Islands, we studied the food brought to the nestlings. A total of 12,800 aerial prey items were identified from 32 food boluses. 97.3% of the prey items were insects, most of which (96%) were from the orders Coleoptera, Diptera, Hemiptera and Hymenoptera. Other orders represented were Dermaptera, Ephemeroptera, Lepidoptera, Mecoptera, Psocoptera and Thysanoptera. Spiders made up 2.6% of the prey items. Prey sizes ranged from 0.5 mm (body length) to 9.7 mm (average 2.46 mm, SD 0.90). There was substantial variation in the prey types among the 32 food boluses, both at the level of orders and of families. Prey size was more similar among the boluses suggesting that prey size was more important than prey type to the swifts. The results are in agreement with previous studies of swift diets.

Echolocation behaviour of Megaderma lyra during typical orientation situations and while hunting aerial prey: a field study

Bats modify the structure and emission pattern of their calls to cope with the functional constraints of a given echolocation situation. As a consequence, the flexibility in sonar call use affects the potential niche use of a species. The present paper addresses call use in Megaderma lyra, a species with a short, broadband multiharmonic basic call, in typical orientation situations, when emerging from and re-entering a day roost, in cruising flight and when passing through vegetation, and during the pursuit of tethered, flying insects. While call duration and emission rate were adapted to the four orientation situations, call spectral composition was similar in these situations, except that bats emitted calls containing more harmonics when re-entering the roost. These moderate call modifications may be accounted for by the observation that M. lyra stayed close to landscape elements even in open habitats. Although M. lyra is a typical gleaner, all tested bats approached flying insects, guided by sonar calls of significantly decreasing duration and pulse interval, and of increasing sweep rate. Before capture, peak frequency was lowered from call to call. The spontaneous approaches towards flying insects with systematic changes in call pattern suggest regular aerial hunting in this species.

Spatial Foraging Behavior and Use of an Urban Landscape by a Fast-Flying Bat, the MolossidTadarida australis

Insectivorous bats require different resources for diurnal roosting and nocturnal feeding, and sound conservation planning requires knowledge of both. However, ranging behavior and habitat use by foraging bats are poorly known, especially within urban ecosystems. We studied foraging flight behavior and use of an urban landscape by 14 white-striped free-tailed bats (Tadarida australis) in metropolitan Brisbane, Australia. Each evening, the bats emerged from day-roosts in tree-hollows and commuted rapidly to a feeding area (median travel speed 42.9 km/h, based on net distances moved during 10–20 min). Within 30 min from emergence their travel speed was greatly reduced (median 6.7 km/h) to a level that remained similar throughout subsequent hours while they foraged. Day-roosts were widely dispersed across the urban landscape, but foraging bats mostly restricted their movements to a localized area of a few kilometers diameter. This area was closer to a communal roost, visited periodically by all bats, than to their day-roosts (median distance from foraging bats to the communal roost 2.5 km; to their day-roosts 6.2 km). The bats showed a significant preference for foraging above floodplain habitat, and did not prefer to feed above remnant forest. T. australis appears tolerant of deforestation and capable of persisting in urban landscapes, provided that roost trees are protected. However, it remains unknown whether a sustained availability of aerial prey depends on floodplains remaining undeveloped.