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Members of the family Phaneropteridae are well known for their acoustical duetting behaviour, used for locating and meeting a mate. In Poecilimon affinis, typically the male approaches a responding female phonotactically. A set of behavioural experiments, bioacoustic and neurophysiological measurements (some with a relatively low sample size, but not repeatable under the same circumstances) indicates the following system: the male song (92 dB SPLpeak at a distance of 1 m) is about 10 dB louder than the female song. The females respond to male signals only if these are ∼15–20 dB above their hearing threshold. The males start a phonotactic approach towards a stationary, responding female only if she is no more than ∼12 m away. Females, on the other hand, may respond to singing males up to a distance of 28m, and to more distant males with softer signals than to closer ones. A possible function of these weak signals, inaudible for the duetting male, may be to attract eavesdropping males. The communic...

Defense of territories in many animal species involves the advertisement of territory holder quality by acoustic signaling. In the sac-winged bat Saccopteryx bilineata, males engage in territorial countersinging when reoccupying their day-roost territories in the morning and in the evening before abandoning the roost for the night. Females roost mainly in male territories, and territory holders are reproductively more successful than nonterritorial males. In territorial songs of male S. bilineata, we distinguished 6 syllable types and parameterized their acoustic properties. The analysis of 11 microsatellite loci allowed assignments of juveniles to their parents. Males had a higher reproductive success both when they uttered more territorial songs per day and when their long buzz syllables had a lower end frequency of the fundamental harmonic. Long buzzes had a harsh quality due to a pulsation of the fundamental frequency at the syllable onset and also had the highest sound pressure level of all syllable types in most territorial songs. Territorial songs and especially long buzz syllables are thus likely to advertise territory holder quality and competitive ability. Copyright 2006.

Vocal group signatures facilitate group cohesion or the exclusion of nongroup members and thus greatly affect the social system of any given species. This is especially significant for highly mobile animals such as bats. The greater sac-winged bat, Saccopteryx bilineata, lives in a harem-based resource defence polygyny with patrilineal kin groups and female-biased natal dispersal. Pups of both sexes produce isolation calls to elicit maternal care. We analysed isolation calls from 25 pups born in seven different social groups in search of vocal signatures. In addition to a constant individual signature, isolation calls exhibited a group signature that became more prominent during ontogeny. Call convergence of fellow pups was independent of relatedness among pups and not driven by maturation effects, showing that the group signature was acquired through social modification, a form of vocal production learning. Behavioural observations of free-living bats indicated that isolation calls were used by adult males to appease more dominant males and to court unfamiliar females. The learned group signature in isolation calls may function as a ‘password’ that reliably associates individuals with their natal colony. This, in turn, could facilitate male harem acquisition and female inbreeding avoidance in the polygynous S. bilineata. The flexibility inherent in the vocal-learning process guarantees that crucial information can be promoted even under shifting social circumstances.

We recorded social vocalizations from two sympatric species of glossophagine bats, Glossophaga soricina and G. commissarisi, using habituated captive groups that were housed in separate flight cages. Whenever possible, the species-specific vocalization types were described in the light of the social context in which they were produced. Several vocalization types within each species’ repertoire had remarkable similarities to vocalization types in the other species’ repertoire. Out of these, four vocalization types with interspecific acoustic similarities (approach pulses, distress calls, aggressive trills, and alert calls) were used in similar behavioral contexts in both species. Approach pulses were produced whenever a bat was flying towards an already occupied roost. Distress calls were uttered whenever a bat was attacked by conspecifics or restrained by the observer, whereas aggressive trills were produced during aggressive encounters prior to physical contact. Alert calls were uttered when bats were disturbed or when several individuals were circling the same location. The interspecific similarity of both the social context and the acoustic structure of vocalization types suggest that the potential for interspecific communication is high in G. soricina and G. commissarisi.

In males of the grasshopper Chorthippus biguttulus the relationship between song and mating success was investigated in three isolated field populations of individually marked animals within their natural habitat. In a population with muted males (forewings removed), females mated on average 1.7 days later than in a population with intact males. But approximately 14 days after the imaginal moult, roughly corresponding with the time of the first oviposition, 100% of females in both populations had mated. In a further test population, females with a choice between singing and mute males mated almost exclusively (16 from 17 observed copulations) with the intact, singing males. The chance encounter frequency of a male and female was equally high for all populations (on average one encounter every 1.2 h). Different encounter probabilities cannot therefore have caused either mating delay in the population with muted males or preferential selection of intact partners.

Summary In mammals, adult behaviour patterns are often expressed by juveniles throughout ontogeny. In bats, many social behaviours develop before pups are weaned, but the ontogeny of social behaviours in juvenile bats is largely unexplored. We studied bat pups’ social behaviour, specifically the solicitations for maternal care in the greater sac-winged bat, Saccopteryx bilineata. Solicitation periods were prolonged (up to 25 min) and consisted of conspicuous behavioural interactions between pups and their mothers. Since solicitation periods could be initiated by pups or mothers, their duration is probably not caused by a conflict over nursing alone. Solicitation periods were the second most prevalent use of activity time in pups. Some pup behaviours resembled the courtship behaviours of adult males and these incipient courtship behaviours occurred most often within solicitation periods. Both length and complexity of solicitation periods increased significantly during ontogeny but there was no significant difference between male and female pups. Also, the activity outside of solicitation periods was not significantly different between pups of both sexes, even though their activity differs remarkably as adults. Prolonged solicitation periods of S. bilineata pups might be comparable to mammalian play and potentially function as practice for adult courtship behaviours.

Most bat species inhabit roosting sites in whichthey are well concealed during the day, such ascaves or tree holes, whereas others roost in exposedlocations on tree trunks or branches (Kunz and Lum -sden, 2003). For the latter, it is essential to appearcryptic in order to avoid predation or disturbance atthe day-roost. Several traits have evolved to enhancethe bats’ cryptic appearance, including cryptic col-oration (e.g., the greenish wings of the foliage-roost-ing bat

Like many other mammals, Saccopteryx bilineata exhibits a polygynous mating system, in which each male defends a group of females called a harem. Colonies consist of several harems, and nonharem males roost adjacent to harems. Unlike most other mammals, females disperse from their natal colony and most juvenile males remain in it. Thus, colonies consist of patrilines, which promotes intense local mate competition. Females are in estrus during a few weeks at the end of the rainy season. Mating is most likely initiated by females and preceded by intense courtship displays of males. Forty percent of colony males do not sire any offspring during their tenure in the colony, whereas a few males can sire up to 6 offspring in a single year. Males use olfactory, visual, and acoustic signals for courtship, and they demonstrate territory ownership by scent marks, lowfrequency calls, and visual displays. Harem males sire on average more offspring than do nonharem males but produce only 30% of the offspring within their own harem territory, with 70% being sired by other harem males or nonharem males. Reproductive success of males increases with decreasing size, fluctuating asymmetry, and fundamental frequency of territorial calls. In addition, females that are closely related to the harem holder are more likely to mate with other males than with the harem holder. Sexual selection in S. bilineata is most likely influenced by intense local mate competition caused by scarce roosts and the patrilineal organization of colonies.

In many animal species, individuals compete for resources but avoid escalated conflicts by threat displays, i.e. a mutual signalling behaviour that enables the opponents to predict the outcome of the conflict without the necessity of actual fighting. For example, territory holders may use acoustic signals to communicate not only their own identity and the borders of their territory but also their competitive quality, fighting ability and motivation. Here, we show that male sac-winged bats, Saccopteryx bilineata, adjust their vocal territorial displays according to the fundamental frequency of territorial songs of their opponents. In playback experiments with territorial males, low-frequency stimuli elicited a higher territorial song rate and length than high-frequency stimuli. Male S. bilineata that sing more often and with lower fundamental frequencies have been shown to sire more offspring than their competitors. Fundamental frequency of territorial songs, hence, may reveal male quality and, consequently, the resulting threat posed to competing males. We argue that this is reflected in the increased response of competitors to low-frequency territorial songs shown here. Such competitive signalling behaviour has been shown in a few mammal species like red deer and baboons but, thus far, not in bats.

We investigated the acoustical component of the recognition process leading to successful mother–pup reunions in the greater sac-winged bat, Saccopteryx bilineata , using both a statistical approach and playback experiments. Statistical evidence for individual distinctiveness was found in the isolation calls uttered by pups and, to a weaker degree, in the echolocation pulse trains emitted by mothers. In contrast to other bat species, isolation calls of S. bilineata pups were complex and multisyllabic, with most of the vocal signature information encoded in the composite syllables at the end of calls. Playback experiments with free-living bats revealed that mothers were able to discriminate between their own pup and an alien young on the basis of isolation calls alone, which confirms the results of the acoustical analysis on vocal signatures in isolation calls. Pups, on the other hand, indiscriminately vocalized in response to echolocation pulse trains from their own and alien mothers, rendering the mother–pup recognition process unidirectional. The one-sidedness of the vocal recognition process in S. bilineata as well as in other bat species might be explained by a lack of selection pressures that shape mutual vocal parent–offspring recognition in other species of mammals and birds. To our knowledge, this study is the first in which playbacks were used to elicit antiphonal calling behaviour between bat mothers and pups experimentally. We argue that vocal responses to playback stimuli are a more feasible and reliable response measure for conducting mother–pup recognition playbacks in bats than the phonotaxis behaviour used in the past.

In the Neotropics ongoing deforestation is producing open and heavily fragmented landscapes dominated by agriculture, mostly plantations and cattle pastures. After some time agriculture often becomes uneconomical and land is abandoned. Subsequent habitat regeneration may be slow because seed inputs are restricted by a lack of incentives--such as suitable roost sites--for seed dispersers to enter deforested areas. Increasing environmental awareness has fostered growing efforts to promote reforestation. Practical and cost-efficient methods for kick-starting forest regeneration are, however, lacking. We investigated whether artificial bat roosts for frugivorous bat species can attract these key seed dispersers to deforested areas, thereby increasing seed rain. We installed artificial bat roosts in a forest-pasture mosaic in the Costa Rican Atlantic lowlands and monitored bat colonization and seed dispersal. Colonization occurred within a few weeks of installation, and 10 species of bats occupied the artificial roosts. Five species of frugivorous or nectarivorous bats colonized artificial roosts permanently in both primary habitat and in deforested areas, in numbers similar to those found in natural roosts. Seed input around artificial roosts increased significantly. Sixty-nine different seed types, mostly of early-successional plant species, were transported by bats to artificial roosts in disturbed habitats. The installation of artificial bat roosts thus successfully attracted frugivorous bats and increased seed inputs into degraded sites. This method is likely to speed up early-vegetation succession, which in turn will attract additional seed dispersers, such as birds, and provide a microhabitat for seeds of mid- and late-successional plants. As well as supporting natural forest regeneration and bat conservation, this cost-efficient method can also increase environmental awareness among landowners.

Since its description in 2001 Alcathoe's myotis (Myotis alcathoe) was recorded from several locations across Europe. Here we describe the first records of this species from Germany, Poland, Albania, and from the European part of Turkey, including the northernmost locality in central Germany (51°23′N, 11°01′E). Compilation of all up-to-date records shows that M. alcathoe has a wide European distribution although it seems to be rare at most places. The habitats where the bat was recorded are natural, moist and deciduous forests with old trees and water streams as can be found, for example, in canyons or forests of alluvial origin. Such habitats suggest that the species probably has a more continuous and wider distribution than currently known and might be expected to occur even further to the North.

Neotropical nectar-feeding bats (Glossophaginae) are highly specialized in the exploitation of floral nectar and have one of the highest mass-specific metabolic rates among mammals. Nevertheless, they are distributed throughout the tropics and subtropics over a wide elevational range, and thus encounter many extreme and energetically challenging environmental conditions. Depressing their otherwise high metabolic rate, e.g., in situations of food restriction, might be an important adaptive physiological strategy in these dietary specialists. We investigated the thermoregulatory behavior of captive 10-g nectar feeding bats (Glossophaga soricina; Chiroptera, Phyllostomidae) under variable ambient temperatures (T a) and feeding regimes and predicted that bats would use torpor as an energy-conserving behavior under energetic constraints. All tested animals entered torpor in response to energetic restrictions and the depth of torpor was dependent on the body condition of the animals and hence on their degree of physiological constraints. Periods of torpor with body temperatures (T b) below 34°C were precisely adjusted to the photoperiod. The median length of diurnal torpor was 11.43 h. The lowest T b measured was 21°C at a T a of 19°C. Estimated energy savings due to torpor were considerable, with reductions in metabolic rate to as low as 5% of the metabolic rate of normothermic bats at the same T a. However, contrary to temperate zone bats that also employ diurnal torpor, G. soricina regulated their T b to the highest possible levels given the present energetic supplies. To summarize, G. soricina is a precise thermoregulator, which strategically employs thermoregulatory behavior in order to decrease its energy expenditure when under energetic restrictions. This adaptation may play a crucial role in the distribution and the assembly of communities of nectar-feeding bats and may point to a general capacity for torpor in tropical bats.

The songflight and the territorial behaviour of courting male pipistrelles (Pipistrellus pipistrellus) were observed in an urban habitat of this bat species, in the city of Bayreuth in Bavaria. (1) Within the city limits, from the middle of July to the end of October but most intensively in September, the male bats occupied courtship territories averaging about 200 m in diameter. At night they patrolled these territories along regular flight routes emitting characteristic advertisement calls. By day they sheltered in crevices in buildings. (2) The courtship territories were densely distributed in the center of the inner city and rarer at the outskirts. As all known larger winter roosts as well as the ‘invasion centers’ (typical late summer swarming sites of this species) also were in the inner city, territories were situated around winter quarters, but not in the vicinity of the nursery roosts, which were lying at the edge of the city and outside it. (3) The males evidently arrange their courtship territories in such a way that as many females as possible pass through them when they inspect the winter roosts. That is, they are not defending resources important to the females; instead, they position their courtship territories near the resources the females require. As male territories are densely packed, the males offer a possibility for mate choice to the females, so that the mating system also bears some likeness to a lek.

SUMMARYEcholocating bats emit ultrasonic calls through their mouth or their nostrils and receive echoes from objects with both their ears. Information conveyed in the echoes is the basis for their three-dimensional acoustic perception of the surroundings. The direction of an object is encoded in binaural echo differences, i.e. on the one hand in the different arrival times of its echo at the two ears, and on the other hand in spectral differences through direction-dependent frequency filtering of head and pinnae. Insufficient attention has been paid, however, to the fact that three-dimensional objects produce structured spatial echo fields, and that the position of the ear in this field determines the echo it receives. We were interested to determine whether the two ears, in addition to direction-specific echo differences, receive object-specific echo disparities that might be useful for the bat. Our measurements with an artificial bat head, which consisted of two microphones and a small ultrasound loudspeaker arranged to resemble a bat's ears and mouth, revealed that echoes at the two ears differed largely depending on the shape and orientation of the echo-giving object. Binaural echo disparities of a bat-pollinated flower did indeed carry information about the orientation and, to a lesser extent, the shape of the flower. During flower approach such object-specific binaural echo disparities even exceed the binaural differences encoding direction of echo incidence, because the echo from the flower in front undergoes the same directional filtering by the two symmetrical ears. Nectar-feeding bats could use these object-specific binaural echo disparities not only to determine the object's orientation relative to the approaching bat, facilitating flight planning, but also to improve object recognition through spatial reconstruction of details of the object creating the echo. Our results suggest that the evaluation of binaural echo disparity has a greater importance for these tasks than has previously been assumed.

We report bat visits to the inflorescences of Marcgravia pittieri. The animals were videotaped visiting the nectaries of the inflorescences in short hovering flight. Nectarivorous bats caught in front of the inflorescences were Anoura cultrata and Hylonycteris underwoodi (both Phyllostomidae: Glossophaginae). Furthermore, we provide a short overview on inflorescence architecture within the genus Marcgravia with a special focus on functional morphology in chiropterophilous species.

SUMMARY Echolocating bats obtain three-dimensional images of their surroundings in complete darkness by emitting sonar signals and evaluating returning echoes. When flying close to objects, bats risk collision and therefore depend on the accuracy of images – particularly in the perceived distance of obstacles, which is coded by the time delay between call and echo. Yet, during flight, such accuracy is perturbed first because bats call and receive echoes at different positions and second because echoes are modified by Doppler shifts. Certain call designs avoid both sources of ranging error, but only for a limited range of distances [the `distance of focus' (DOF)]. Here, we show that whiskered bats (Myotis mystacinus) using broadband echolocation calls adjust call design in a range-dependent manner so that nearby obstacles are localised accurately. Such behaviour is adaptive because it reduces collision risk. The bats also reduced call duration to some extent as they approached obstacles so that most returning echoes arrived after they finished calling. This reduction in call duration during the approach to obstacles was neither the only nor the main factor that influenced DOF. Indeed, both duration and bandwidth of calls influenced DOF independently, with lower bandwidths and longer durations giving greater DOF. Our findings give a new perspective on the adaptive significance of echolocation call design in nature and have implications for sonar engineering.

Chorthippus lacustris is an endemic grasshopper (Orthoptera) species in Epirus, Greece. Its population status, habitat characteristics, and relation to historical and current human land use are investigated. The species has a restricted and fragmented distribution pattern. Five locations, four within Pamvotida Lake basin and one in Lake Paramythia, cover a total of 0.12 km2. It is strongly dependent on wet grasslands, flooded on a seasonal basis. The greatest population density is recorded in the site with the greatest diversity of dominant plant species. Ch. lacustris is estimated to have lost 85–99% of its habitat during the last 50 years due to wetland drainage. The main threat to the species survival is further habitat loss by urbanisation around Pamvotida Lake and by land conversion to agriculture in Paramythia Lake, even though both sites belong to the Natura 2000 network. The species status is Critically Endangered and it should be listed in Annex II of the Habitat Directive (92/43/EEC) as a priority species for conservation. Restoring wet grasslands, protecting them from further urbanisation and drainage, and monitoring species population are the main measures proposed for its conservation.

We studied the echolocation calls emitted by Phyllops falcatus (Chiroptera: Phyllostomidae) during foraging, in the field and in the lab. Calls emitted in free flight, in a more or less uncluttered situation, were about 4.5 ms (up to 5.3 ms) long and characterized by a sweep of the first harmonic (= fundamental) from ca. 73 kHz down to about 23 kHz, which is unusually large for phyllostomid bats. A less intense second harmonic was always present. The intervals between pulses varied between 55 and 170 ms with a mean of about 110 ms. During approach to bushes or trees (or during flight in confined space between bushes), or in the flight room, calls became shorter (ca. 2 ms) and more energy was allocated to the second harmonic, sometimes also a third harmonic appeared. During approach to a fruit calls were further shortened (about 1 ms or less), and call frequency increased to about 5 calls/100 ms, calls often being grouped. The large bandwidth of the first harmonic separates Phyllops from all other Cuban bat species and allows identification in the field.

In the duetting grasshopper Chorthippus biguttulus, a female's decision to reply to a conspecific male is based on the evaluation of a number of features of the male's song, which consists of uninterrupted syllables separated by pauses. Female responses are tuned to a restricted range of pause durations. However, males produce songs with noisy rather than silent pauses, which should make the measurement of pause durations more difficult for the female. We examined the adaptive value of these noisy pauses by testing female responses to (1) pairs of natural phrases, which differed only with respect to clear or noisy syllable pauses, and (2) synthetic phrases, in which the syllable onset accentuations and noise levels in the pauses were systematically varied. There was considerable variation between females, both in their preference for clear or noisy pauses in natural phrases, and in the optimal combinations of syllable onset accentuations and noise levels in pauses that they preferred in synthetic phrases. The response profiles of individual females were consistent. The experiments with synthetic phrases showed that, on average, females preferred more extreme values of syllable onset accentuations than were present in male songs. Noisy pauses increased the range of syllable pause durations accepted by females. The results suggest that noisy pauses could buffer signallers against the negative consequences of both signal degradation during transmission and extreme receiver choosiness.

Vocalisations of many songbirds, anurans, and insects are shaped by sexual selection. Males acoustically compete for territories, and females choose their mates by means of male courtship songs. In courtship, richness and complexity of elements are often favoured characters. Only a few examples of complex songs are known in mammals. Males of the harem-polygynous sac-winged bat (Saccopteryx bilineata, Emballonuridae) have an uncommonly complex vocal repertoire, and different song types of males are used in the context of territorial defence and in courting females. We classified the daytime vocalisations of 16 male S. bilineata from a colony in Costa Rica, both on the basis of their acoustical properties and the social context in which they occurred. Seven vocalisation types were differentiated: echolocation pulses, barks, chatter, whistles, screeches, territorial songs and courtship songs. Territorial songs were short, rather stereotyped and not obviously directed towards a certain conspecific. They appear to be of importance in male competition for harem territories, in which females roost during the day. Courtship songs were exclusively observed when males displayed towards a female; they were long and complex, and consisted of highly variable elements (“calls”). We classified the calls in courtship songs of six males into call types, based on acoustical properties, mainly spectral purity and duration. Four call types are described in detail: trills, noise-bursts, “short tonal” calls, and “quasi constant frequency” calls. Twelve parameter values were extracted from the most common call type, the trill. Discriminant function analysis of trills showed that different males had different repertoires. This could allow females to use trill parameters for recognition of individual males and thus for mate choice.

Glossophagine bats (Phyllostomidae, Glossophaginae) are specialized visitors to the flowers of several hundred species of neotropical plants. They are able to exploit flowers in hovering flight by imbibing nectar with a highly protrusile brush-tip tongue. As tongue extension is achieved by muscular and vasohydraulic mechanisms, its operational length can be inferred only from actively feeding animals. For this study, we measured maximum tongue extensions during nectar feeding in 9 species of glossophagine bats. We trained bats to feed from vertically oriented glass test tubes (9- and 15-mm inside diameter). The maximum depth of nectar drainage by a bat was recorded as maximum operational tongue length. Measured operational tongue lengths were in the range of the total body length of bats. The record length was 77 mm (in tubes with 15-mm inside diameter) in the 17-g flower specialist Choeronycteris mexicana. This compares with only 11–24 mm in the nonglossophagine frugivorous bat Carollia perspici...

SUMMARY Nectar-feeding glossophagine bats searching for flowers are guided by their echolocation system as well as olfactory cues in detecting and recognizing nectar sources. Therefore, chiropterophilous plants, which depend on these bats as pollinators, may be expected to have evolved acoustically conspicuous flowers that facilitate detection. As it is poorly understood how bats manage to find and recognize flowers acoustically, we investigated the echoes of some of the flowers pollinated by bats. Echoes of bell-shaped bat-pollinated flowers have characteristic features with respect to the echoes they reflect to a calling bat and differ from the echoes of leaves or other objects in their surroundings: the echoes are comparatively long and of complex spectral composition. Owing to the specific shape of the flowers, characteristic `spectral directional patterns' result when the spectra of the echoes are plotted against the angle of sound incidence. We suggest that bats are able to recognize such flowers — and probably other objects as well — not only by a characteristic spectral composition of the echo but also by comparing sequential echoes, at the same time taking into account their exact calling position relative to the object.

We analysed the polygynous mating system of the bat Saccopteryx bilineata using behaviour observations and genetic data on 11 microsatellite DNA loci. Basic social units in S. bilineata are harem groups that consist of single males and up to eight females. Colonies comprise several harem groups, and the composition of colonies and harems is often stable over several reproductive seasons. The combination of parentage exclusion and likelihood-based parentage assignment in this study produced detailed parentage information for a large colony of S. bilineata. Reproduction occurred mostly within the colony (17% extra-colony paternity), but social associations in harems within the colony did not represent reproductive units (70% extra-harem paternity). The latter finding was consistent over three reproductive seasons. Spatial association of the roosting sites of males and females could not explain parentage patterns in the colony. Even though intra-harem paternity was less frequent than expected, it contributed significantly to reproduction of harem males. On average, the number of offspring sired by a male with females in his harem territory increased significantly with harem size, which corresponds to the higher energetic investment that is related to the maintenance of large harems. However, extra-harem paternity was not correlated with a male's harem size or intra-harem reproductive success. This suggests that individual preferences of females rather than male traits associated with the ability to defend large harems are most likely to cause the detected differences between social association and genetic mating system.

Alternative tactics in reproductive behavior enable individuals to maximize their fitness in relation to competitors in the same population. In many taxa, territoriality is a common tactic of males to increase their reproductive success. In the bat Saccopteryx bilineata, territorial males defend roosting areas for females against other males and court females throughout the year. Peripheral males in the same colonies do not defend territories but compete with territorial males for reproduction with females. In this study, we monitored the behavior of the males in a natural colony over three reproductive seasons. We compared morphological and age data and measured the reproductive output of males adopting the territorial or peripheral tactic. No differences in body size or weight were detected between male types, but the probability of adopting a tactic seemed to be age dependent. Peripherals were often young males and replaced territorials in several cases, whereas the opposite case was not observed. Peripherals were not excluded from reproduction, but territorials were more likely to reproduce. Variation in reproductive success was high within both male tactics, and the reproductive success of some peripherals was comparable to territorials, but, on average, the reproductive success of territorials was more than twice as high. Therefore, behavioral tactics do not seem to be equally profitable in general but may represent different phases in the reproductive life of many S. bilineata males. Copyright 2002.

Saccopteryx bilineata has a polygynous mating system in which males defend females in a harem territory. Harem defense and courtship include energetically costly flight maneuvers and hovering displays. We tested if (1) harem males have a greater field metabolic rate than non-harem males or females and if (2) the field metabolic rate of harem males is correlated with the number of females in a harem territory. We measured the energy budget in 32 S. bilineata with the doubly labeled water method and compared these estimates with behavioral observations in the daytime roost. Among adult bats, field metabolic rate varied with body mass by an exponent of approximately two. We found no significant difference in field metabolic rate or mass-specific field metabolic rate between harem and non-harem males. The mass-specific field metabolic rate of harem-males increased with harem size. The latter finding supports the hypothesis that the energy costs of courtship display and territorial defense influence the energy budget of harem males. Overall, field metabolic rates of S. bilineata were lower than those of similarly sized bats of the temperate zone and only 2.3 times above the basal metabolic rate recorded for this species. We suggest that male S. bilineata did not take advantage of their metabolic capacity because a prudent allocation of energy to activities of harem maintenance is an adaptive strategy for males in this mating system.

The hearing range of the tettigoniid Phaneropterafalcata for the echolocation calls of freely flying mouseeared bats (Myotis myotis) was determined in the field. The hearing of the insect was monitored using hook electrode recordings from an auditory interneuron, which is as sensitive as the hearing organ for frequencies above 16 kHz. The flight path of the bat relative to the insect's position was tracked by recording the echolocation calls with two microphone arrays, and calculating the bat's position from the arrival time differences of the calls at each microphone. The hearing distances ranged from 13 to 30 m. The large variability appeared both between different insects and between different bat approaches to an individual insect. The escape time of the bushcricket, calculated from the detection distance of the insect and the instantaneous flight speed of the bat, ranged from 1.5 to more than 4s. The hearing ranges of bushcrickets suggest that the insect hears the approaching bat long before the bat can detect an echo from the flying insect.

Field studies of elusive mammals such as Agouti paca are difficult, and results are often biased and incomplete because the animals are nocturnal and avoid traps. By studying an A. paca population in a Pacific lowland forest of Costa Rica, we developed indirect observational methods to estimate population density and food resource utilization. To estimate population density, we divided the number of A. paca burrows found in a 12-ha census area by the average number of burrows utilized per individual from radiotelemetry data. We compared this estimate to independent population estimates obtained using two transect methods. Agouti paca density was estimated at 93 individuals/km2 based on burrow number, and between 67 to 70 individuals/km2 using transect methods. This discrepancy corroborates previous studies suggesting that transect methods underestimate population density. To identify food resources consumed by the species, we collected fruits and seeds with unambiguous A. paca teeth marks. The only animal in Central America with an incisor width similar to A. paca. is Dasyprocta variegata; in a comparison of both species, however, we found that A. paca had a significantly larger incisor width and that teeth marks of 4 mm or wider unambiguously indicated handling by this species. By applying this technique, food resources utilized by A. paca can be identified more easily than by direct observation. At our study site, we identified 33 plant species consumed by A. paca; 61 percent are new records for this animal. Our results suggest that A. paca plays a major, although not fully understood, ecological role in seed predation and dispersal. RESUUMEN Estudios de campo sobre mamiferos elusivos como las Agouti para son intensivos tanto en tiempo como en labor, y resultan frequentemente parcialisados y incompletos debido a que estos animales son nocturnos y le temen a las trampas. Durante un estudio de la poblaci6n de A. paca en un bosque lluvioso de Cosca Rica, desarrollamos metodos de observacion indirectos para estimar la densidad y uso de recursos de la poblacion. Para estimar la densidad de la poblacion, dividimos el nlimero de madrigueras en el area de doce hectareas por el numero promedio de madrigueras utilizados por un individuo de los resultados de radiotelemetria. Comparamos esto estimado con otros obtenidos independientemente por metodos de transecto. Basado en el numero de madrigueras, se estimo la densidad de A. paca en 93 animales/km2, mientras que los estimados basados en observaciones de transectos dio entre 67 a 70 animaled km2. Tal diferencia podria confirmar estudios previos indicando que los metodos de transecto subestiman la densidad de poblaciones. Con el fin de identificar 10s recursos alimenticios consumidos por esta especie, recolectamos frutos y semillas marcas dentales de pacas. El unico animal en America Central con un ancho de diente incisivo similar al de la A. paca es Dasyprocta uariegata. En una comparacion de las dos especies encontramos que las A. puca tenian incisivos significativamente mas anchos, y que marcas dentales de 4 mm o mas indican sin ambiguedad manipulacion por esta especie. Aplicando esta tecnica, se puede identificar los recursos alimenticios utilizados por A. paca mas facilmente que mediante observaciones directas. En nuestro sitio de estudio identificamos 33 especies de plantas consumidas por pacas: 61 porciento son registros nuevos para este animal. Nuestros resultados indican que las A. paca representan una parte muy importante, pero todavia no muy bien entendida, en la depredacion y dispersion de semillas.

We studied the paternity in a colony of the harem-polygynous white-lined bat Saccopteryx bilineata by microsatellite typing and compared the data with group composition and stability. Although we recorded a high stability for harem groups, neither spatial proximity of males to harem females nor harem ownership allowed us to predict the paternity of the next year's harem offspring. Eight out of 28 juveniles were fathered by holders of the harem in which they were born, while the other 20 represent Extra-Harem-Young (EHY). 50% of EHY were fathered by males from outside the colony and 50% by other harem holders or peripheral males of the colony. On average, reproductive success of harem holders (1.2 offspring/year) was higher compared with peripheral males (0.4 offspring/year). Harem size seemed not to influence reproductive success of harem holders. Although maintaining of a territory seems to be costly for a harem male, his ability to control the females of his harem may be restricted; instead female Saccopteryx bilineata appear to have a high potential for female choice.

The flower scents of 11 bat-pollinated plant species have been investigated using the 'closed-loop-stripping'-adsorption technique. GC and GC/MS analyses of the headspace samples resulted in the identification of 49 compounds, comprising amongst others sulphur compounds, terpenoids and aliphatic compounds.

Many gomphocerine grasshoppers communicate acoustically: a male's calling song is answered by a female which is approached phonotactically by the male. Signals and recognition mechanisms were investigated in Chorthippus biguttulus with regard to the cues which allow sex discrimination. (1) The stridulatory files on the hindfemur of both sexes are homologous in that they are derived from the same row of bristles, but convergent with respect to the “pegs”. In males the pegs are derived from the bristles, and in females from the wall of the bristle's cup. (2) Male and female songs are generated by similar, probably homologous motor programs, but differ in the duration, intensity, “gappyness” of syllables, risetime of pulses, and the frequency spectra. The hindleg co-ordination during stridulation and the resulting temporal song patterns are less variable in males than in females. (3) For both sexes, recognition of a mate's signal depends on species-specific syllable structure. For males it is essential that the female syllables consist of distinct short pulses, whereas females reject “gappy” syllables. Males strongly prefer “ramped” pulses, females respond to syllables irrespective of steeply or slowly rising ramps. Males react only to the low-frequency component, whereas females prefer spectra containing both, low and high frequency components.

We studied the interaction between the bromeliad Werauhia gladioliflora and its flower visitors in the Caribbean lowland forest of Costa Rica, in order to quantify the mutual benefits to both partners. Over 6 y, the bromeliads flowered mainly between October and December; with an individual inflorescence flowering for an average of 34 d (n = 233 inflorescences). The bromeliad showed a flexible breeding system with autogamy occurring in addition to cross-pollination. Exclusive pollinators were small nectar-feeding bats (Phyllostomidae: Glossophaginae). The average volume of nectar produced per flower was 1.1 ml (n = 25 flowers). The main visitor was the bat Glossophaga commissarisi, which approached the flowers exclusively using hovering flight. Visitation by bats, measured by infrared light sensors, occurred throughout the night with an activity peak after midnight. Median hovering duration of the bats at the flowers was 320 ms (n = 1246 visits). Hourly mean of hovering duration was negatively correlated with hourly nectar secretion rate. The flower visitation behaviour of a bat over the night seems to be shaped by a combination of intrinsic physiological factors and by nectar availability. Size of both flowers and visitors make Werauhia gladioliflora a very accessible system for quantification of factors affecting evolution of bat–plant interactions.

1. Chorthippus dorsatus, Ch. dichrous and Ch. loratus are closely related, sympatric grasshopper species (subfam. Gomphocerinae) with few morphological differences. 2. Songs of males contain two elements: pulsed syllables produced during synchronous movements of the hindlegs (part A) and ongoing noise produced during alternating movements of the hindlegs (part B). Part A predominates in songs of Ch. loratus and part B in songs of Ch. dichrous. In Ch. dorsatus both parts contribute nearly equally to the songs. 3. Ch. dichrous and Ch. loratus are Eastern species, while Ch. dorsatus occurs all over Europe including Spain and Italy. The songs of different populations of Ch. dorsatus in Europe are compared. 4. Female stridulation of the three species is similar to male stridulation. 5. Females prefer—expressed by their response songs—the conspecific signals over heterospecific ones. Discrimination, however, is not perfect. 6. Tested with artificial song models, females of the different species differ ...

The visual splendor of many diurnal flowers serves to attract visually guided pollinators such as bees and birds, but it remains to be seen whether bat-pollinated flowers have evolved analogous echo-acoustic signals to lure their echolocating pollinators. Here, we demonstrate how an unusual dish-shaped leaf displayed above the inflorescences of the vine Marcgravia evenia attracts bat pollinators. Specifically, this leaf's echoes fulfilled requirements for an effective beacon, that is, they were strong, multidirectional, and had a recognizable invariant echo signature. In behavioral experiments, presence of the leaves halved foraging time for flower-visiting bats.

The Chorthippus biguttulus group distributed in the west Palaearctic, while intensively examined in Europe, is poorly known in the glacial refugia such as Anatolia. This produces constraints in making accurate statements about evolution and the biogeography of the group. The C. brunneus subgroup of this lineage is examined using large amounts of morphological and song data from Anatolia (Asian Turkey) and representatives from Europe. Song and morphology in combination suggested three species to be found in Anatolia. The first is C. bornhalmi Harz which is also known from south-east Europe. The other two are new species: Chorthippus antecessor sp. n. and Chorthippus relicticus sp. n.. Morphologically, C. antecessor sp. n. is the most aberrant species of the C. brunneus subgroup, but is similar to C. bornhalmi in song. The specific song and morphology (the aberrant number of stridulatory pegs) define C. relicticus as a new species and both also indicate that it is closely related to C. brunneus and C. jacobsi. A song and morphology based phyloylogenetic assumption for C. brunneus subgroup suggests C. antecessor, C. bornhalmi and C. miramae to constitute one clade and C. brunneus, C. jacobsi and C. relicticus another. The scenario suggested for their evolution assume the following steps: (i) divergence of C. bornhalmi from a C. antecessor like ancestor, (ii) derivation of an ancestral population (which later give rise to C. brunneus + C. jacobsi + C. relicticus) from a C. bornhalmi like ancestor, and (iii) later fragmentation of this ancestral population to result in the present three species (C. brunneus + C. jacobsi + C. relicticus). All of these events seem to be correlated with the climatic cycles during Pleistocene. The conclusion is that the two new species are range-restricted, vulnerable species as is the case for many other taxa present in the Mediterranean Taurus biodiversity hotspot.

Background Bats of the family Phyllostomidae show a unique diversity in feeding specializations. This taxon includes species that are highly specialized on insects, blood, small vertebrates, fruits or nectar, and pollen. Feeding specialization is accompanied by morphological, physiological and behavioural adaptations. Several attempts were made to resolve the phylogenetic relationships within this family in order to reconstruct the evolutionary transitions accompanied by nutritional specialization. Nevertheless, the evolution of nectarivory remained equivocal. Results Phylogenetic reconstructions, based on a concatenated nuclear-and mitochondrial data set, revealed a paraphyletic relationship of nectarivorous phyllostomid bats. Our phylogenetic reconstructions indicate that the nectarivorous genera Lonchophylla and Lionycteris are closer related to mainly frugivorous phyllostomids of the subfamilies Rhinophyllinae, Stenodermatinae, Carolliinae, and the insectivorous Glyphonycterinae rather than to nectarivorous bats of the Glossophaginae. This suggests an independent origin of morphological adaptations to a nectarivorous lifestyle within Lonchophyllinae and Glossophaginae. Molecular clock analysis revealed a relatively short time frame of about ten million years for the divergence of subfamilies. Conclusions Our study provides strong support for diphyly of nectarivorous phyllostomids. This is remarkable, since their morphological adaptations to nutrition, like elongated rostrums and tongues, reduced teeth and the ability to use hovering flight while ingestion, closely resemble each other. However, more precise examinations of their tongues (e.g. type and structure of papillae and muscular innervation) revealed levels of difference in line with an independent evolution of nectarivory in these bats.

Mating in the bushcricket Metaplastes ornatus Ramme 1931 entails a number of peculiar genital couplings that precede the transfer of the large spermatophore. During these “phase-I couplings,” the male introduces his specially structured subgenital plate into the female's genital chamber, performs back-and-forth movements, and turns her genital chamber inside out when he withdraws, whereupon the female carefully cleans her everted genital chamber with her mouthparts. During the last coupling (phase II) the male's subgenital plate is not introduced but the large spermatophore, which averages 22% of a male's body weight, is transferred. Counts of sperm in the spermathecae of females suggested that the phase-I couplings, which occur prior to spermatophore transfer, function to remove, or at least to reduce, the sperm of a female's previous mates. The form of the keel of the male's subgenital plate, its position within the female's genital tract during phase-I couplings, and the back-and-forth movements suggest that the male may stimulate release of sperm from the female's spermatheca by a mechanism similar to fertilization as eggs pass through the genital chamber during oviposition.

Auditory interneurones originating in the metathoracic ganglion of females of the grasshopper Chorthippus biguttulus were investigated with respect to their processing of models of the male’s song. In these models two temporal configurations were varied: (i) the song pattern, consisting of ‘syllables’ and ‘pauses’, and (ii) the duration of short gaps within syllables. A precise encoding of the song pattern is found only among receptors and ‘thoracic’ neurones (SN1, TNI), but not among ascending neurones. The only ascending neurone that reacts tonically at all intensities (AN6) encodes the song pattern much less precisely than do receptors. Other ascending neurones (AN3, AN11) encode the gross pattern of model songs, but only at low intensities. One spontaneously active ‘local’ neurone (SN6) is tonically inhibited and encodes the pauses of a model song. A similar response, however, is not found in three ascending neurones (AN13, AN14, AN15), which are merely inhibited. Among ascending neurones, AN12 is the most reliably influenced by the syllable-pause structure of the songs. Its phasic burst marks the onset of every syllable in a behaviourally attractive song. Its activity could account for the rising part of the corresponding behavioural response curve. However, no ascending neurone shows activity corresponding to the falling part of the behavioural response. Among local neurones, the phasic BSN1 neurones are most clearly influenced by varying syllable-pause combinations. Gaps within the song syllables cause a complete inhibition of the activity of AN4. The response of AN4 to syllables with and without gaps is strikingly similar to the behavioural response and is maintained over the whole intensity range tested. Several local neurones, especially SN6, are strongly influenced by gaps within model songs - though only in certain intensity ranges. In accordance with behavioural results, the pathways for information on song pattern and sound direction appear to be separated among ascending neurones. Among local interneurones, however, this separation does not appear to take place, since the most directional local neurone, BSN1, might also be suited for pattern-filtering tasks.

SUMMARY Nectar feeding bats use echolocation to find their flowers in the dense growth of tropical rainforests, and such flowers have evolved acoustic features that make their echo more conspicuous to their pollinators. To shed light on the sensory and cognitive basis of echoacoustic object recognition we conducted a size discrimination experiment with the nectarivorous bat Glossophaga soricina and compared the bats' behavioural performance with the echoic features of the training objects. We chose a simple geometric form, the hollow hemisphere, as the training object because of its resemblance to the bell-shaped concave form of many bat flowers, as well as its special acoustic qualities. The hemispheres showed a characteristic echo pattern, which was constant over a wide range of angles of sound incidence. We found systematic size-dependent changes in the echo's temporal and spectral pattern as well as in amplitude. Bats were simultaneously confronted with seven different sizes of hollow hemispheres presented from their concave sides. Visits to one particular size were rewarded with sugar water, while we recorded the frequency of visits to the unrewarded hemispheres. We found that: (1) bats learned to discriminate between hemispheres of different size with ease; (2) the minimum size difference for discrimination was a constant percentage of the hemisphere's size (Weber fraction: approximately 16% of the radius); (3) the comparison of behavioural data and impulse response measurements of the objects' echoes yielded discrimination thresholds for mean intensity differences (1.3 dB), the temporal pattern (3-22 μs) and the change of spectral notch frequency(approximately 16%). We discuss the advantages of discrimination in the frequency and/or time domain.

Infant babbling in humans and a few other primates plays an important role in allowing the young to practice the adult vocal repertoire during early behavioral development. Vocalizations uttered during babbling resemble, to some degree, the acoustic structure of adult vocalizations and are often produced in long bouts independent of any social context. Similar behavior, termed subsong or plastic song, is known from a variety of songbirds. Here, we show that pups of the sac-winged bat (Saccopteryx bilineata), a species with an unusually large vocal repertoire, produce renditions of all known adult vocalization types during bouts of vocalizations, which appear to be independent of a distinct social context. Babbling occurs in pups of both sexes, even though only adult males, not females, utter all different vocalization types produced in infancy. To our knowledge, this is the first evidence of babbling in a nonprimate mammal and suggests that infant babbling may be necessary for the ontogeny of complex vocal repertoires.

During doubly-labelled water (DLW) experiments, blood collection by venous puncture may traumatize animals and consequently affect the animals' behaviour and energy budget. Recent studies have shown that blood-sucking bugs (Triatominae; Heteroptera) can be used instead of conventional needles to obtain blood from animals. In this paper, we validate the bug method in captive nectar-feeding bats, Glossophaga soricina, for water budget analysis by comparing the daily water flux estimated with the DLW method with values measured by an energy balance method. As the mean daily water flux of the DLW method was not significantly deviating from the expected value, blood-sucking bugs may substitute more invasive methods of blood collection in DLW experiments. Based on the DLW estimates, daily energy and water intake rates were calculated and compared to values measured with the energy balance method. The DLW method and the energy balance method yielded on average similar results regarding the daily energy intake (DLW method: 48.8+/-14.2 kJ d(-1) versus energy balance method: 48.1+/-9.9 kJ d(-1)) and daily water intake (DLW method: 13.7+/-2.4 mL d(-1) versus energy balance method: 14.7+/-3.0 mL d(-1)). Based on the calculated water and sugar intake per day, we estimated the sugar concentration of ingested nectar to equal on average 16.2+/-2.4% (mass/mass), which fell close to the measured sugar concentration of 17% (mass/mass) bats fed on during the experiment. We conclude that it is possible to extrapolate mean daily energy and water intake for animal groups, populations and species based on DLW estimates, but due to the large variance of results (low accuracy), it seems inadequate to calculate values for single individuals.

Most mammals, with the exception of primates, have dichromatic vision and correspondingly limited colour perception1. Ultraviolet vision was discovered in mammals only a decade ago2, and in the few rodents and marsupials where it has been found, ultraviolet light is detected by an independent photoreceptor2,3. Bats orient primarily by echolocation, but they also use vision. Here we show that a phyllostomid flower bat, Glossophaga soricina, is colour-blind but sensitive to ultraviolet light down to a wavelength of 310 nm. Behavioural experiments revealed a spectral-sensitivity function with maxima at 510 nm (green) and above 365 nm (ultraviolet). A test for colour vision was negative. Chromatic adaptation had the same threshold-elevating effects on ultraviolet and visible test lights, indicating that the same photoreceptor is responsible for both response peaks (ultraviolet and green). Thus, excitation of the β-band of the visual pigment is the most likely cause of ultraviolet sensitivity. This is a mechanism for ultraviolet vision that has not previously been demonstrated in intact mammalian visual systems.

We analysed the polygynous mating system of the bat Saccopteryx bilineata using behaviour observations and genetic data on 11 microsatellite DNA loci. Basic social units in S. bilineata are harem groups that consist of single males and up to eight females. Colonies comprise several harem groups, and the composition of colonies and harems is often stable over several reproductive seasons. The combination of parentage exclusion and likelihood-based parentage assignment in this study produced detailed parentage information for a large colony of S. bilineata. Reproduction occurred mostly within the colony (17% extra-colony paternity), but social associations in harems within the colony did not represent reproductive units (70% extra-harem paternity). The latter finding was consistent over three reproductive seasons. Spatial association of the roosting sites of males and females could not explain parentage patterns in the colony. Even though intra-harem paternity was less frequent than expected, it contributed significantly to reproduction of harem males. On average, the number of offspring sired by a male with females in his harem territory increased significantly with harem size, which corresponds to the higher energetic investment that is related to the maintenance of large harems. However, extra-harem paternity was not correlated with a male's harem size or intra-harem reproductive success. This suggests that individual preferences of females rather than male traits associated with the ability to defend large harems are most likely to cause the detected differences between social association and genetic mating system.

Different species of bat can be morphologically very similar. In order to estimate the amount of cryptic diversity among European bats we screened the intra- and interspecific genetic variation in 26 European vespertilionid bat species. We sequenced the DNA of subunit 1 of the mitochondrial protein NADH dehydrogenase (ND1) from several individuals of a species, which were sampled in a variety of geographical regions. A phylogeny based on the mitochondrial (mt) DNA data is in good agreement with the current classification in the family. Highly divergent mitochondrial lineages were found in two taxa, which differed in at least 11% of their ND1 sequence. The two mtDNA lineages in Plecotus austriacus correlated with the two subspecies Plecotus austriacus austriacus and Plecotus austriacus kolombatovici. The two mtDNA lineages in Myotis mystacinus were partitioned among two morphotypes. The evidence for two new bat species within Europe is discussed. Convergent adaptive evolution might have contributed to the morphological similarity among distantly related species if they occupy similar ecological niches. Closely related species may differ in their ecology but not necessarily in their morphology. On the other hand, two morphologically clearly different species (Eptesicus serotinus and Eptesicus nilssonii) were found to be genetically very similar. Neither morphological nor mitochondrial DNA sequence analysis alone can be guaranteed to identify species.

The male song of the duetting grasshopper Chorthippus biguttulus consists of syllables alternating with noisy pauses. The syllable-pause structure is important for song recognition by the female. Using playback experiments we investigated the mechanism by which intensity modulations within the song pattern are used to detect syllable onsets and offsets. We varied the relative onset level (level of the syllable beginning relative to the noisy pause) and the relative offset level (level of the noisy pause relative to the syllable end) independently in different experiments. For all females, an increase in intensity defining the syllable onset was necessary to evoke responses. Syllable offset cues were not always necessary: some females responded to continuous noise stimuli wherein only syllable onsets were marked by short pulses of high intensity. Those females that did not require syllable offset cues did not, however, lack a functional pause detection mechanism, since their responses to model songs containing silent pauses were restricted to a given range of pause durations. We propose that syllable-pause detection involves two independent processes: (1) syllable onset detection by a phasic neuronal unit that can be re-activated only after a short pause, and (2) the rejection of unacceptably long pauses by a second unit.

The habitat preferences and activity of greater mouse-eared bats were investigated by means of radio-telemetry in two regions in Upper Franconia (Bavaria, Germany) that are characterized by a mosaic of deciduous forests, coniferous forests and woodless areas. In one case bats roosted in a maternity colony from which they visited foraging habitats up to 10.8 km away; in the second, the bats started in a cave which served as a night roost. These bats foraged around the cave up to 2.5 km away. Mean size of foraging areas was 13.1 ± 4.6 ha. Most of the bats used several foraging areas per night (mean 5.1, range 1–10). Hunting time per foraging site ranged from 5 to 224 (median 25) minutes. Foraging habitats in some individuals remained constant over two consecutive years. The bats hunted almost exclusively in woodland (98% of the hunting time) with a significant preference for deciduous forests as opposed to coniferous forests. The preference for deciduous forests as foraging habitats is likely to be caused b...