THE SPECIES-REPERTOIRE OF WHISTLED SONGS IN THE EUROPEAN STARLING: SPECIES- SPECIFIC CHARACTERISTICS AND VARIABILITY

ABSTRACT

Observations of European starlings in France, Germany and Australia reveal surprising high similarities in the individual repertoires of whistled songs. The structure of the whistles enabled us to recognize a number of categories, in which some species-specific themes were found everywhere. They appear with the same general characteristics and variation ranges in all populations.

There seems therefore to be a basic species-specific repertoire common to all males, who have also a number of additional individual themes which characterize each male in its colony. These individual themes show also common characteristics in the different populations. The results suggest that a mechanism has evolved which canalizes the patterns to be learned. The existence of such a universal innate species-specific repertoire has also to be related to functional aspects and to the complicated dialects found in this species.     

BUZZING BEES: COMMUNICATION BETWEEN BUMBLE BEE SOCIAL PARASITES (HYMENOPTERA: APIDAE) AND THEIR HOSTS

ABSTRACT

Although sounds are produced by highly eusocial bees in a variety of contexts, their meaning and evolution are poorly understood. In this study we examined the communicative function of sound during dominance disputes in primitively eusocial bumble bees (Hymenoptera: Apidae). The interaction between sound production and dominance behaviour was studied in the context of parasitism by obligate bumble bee social parasites (Psythyrus spp.). Females of Psithyrus bohemicus and P. vestalis produced sound during dominance interactions in bumble bee host colonies. Parasites mauled and pushed host bees, after which they buzzed with their wings folded. The sounds were broad band, with a mean frequency of 820 Hz for the loudest harmonic produced by a P. bohemicus female. The frequency range of recorded sounds matched that of the vibratory stimuli to which isolated bumble bee workers responded. Buzzing by some bumble bee social parasites may assist them in advertising a position of dominance in egg-laying hierarchies established in the absence of pheromonal inhibition of ovarian development.     

FM signals produce robust paradoxical latency shifts in the bat’s inferior colliculus

Previous studies in echolocating bats, Myotis lucifugus, showed that paradoxical latency shift (PLS) is essential for neural computation of target range and that a number of neurons in the inferior colliculus (IC) exhibit unit-specific PLS (characterized by longer first-spike latency at higher sound levels) in response to tone pulses at the unit’s best frequency. The present study investigated whether or not frequency-modulated (FM) pulses that mimic the bat’s echolocation sonar signals were equally effective in eliciting PLS. For two-thirds of PLS neurons in the IC, both FM and tone pulses could elicit PLS, but only FM pulses consistently produced unit-specific PLS. For the remainder of PLS neurons, only FM pulses effectively elicited PLS; these cells showed either no PLS or no response, to tone pulses. PLS neurons generally showed more pronounced PLS in response to narrow-band FM (each sweeping 20 kHz in 2 ms) pulse that contained the unit’s best frequency. In addition, almost all PLS neurons showed duration-independent PLS to FM pulses, but the same units exhibited duration-dependent PLS to tone pulses. Taken together, when compared to tone pulses, FM stimuli can provide more reliable estimates of target range.     

The use of cattle Bos taurus for restoring and maintaining holarctic landscapes: Conclusions from a long‐term study (1946–2017) in northern England

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Dose finding - a challenge in statistics

A good understanding and characterization of the dose response relationship of any new compound is an important and ubiquitous problem in many areas of scientific investigation. This is especially true in the context of pharmaceutical drug development, where it is mandatory to launch safe drugs which demonstrate a clinically relevant effect. Selecting a dose too high may result in unacceptable safety problems, while selecting a dose too low may lead to ineffective drugs. Dose finding studies thus play a key role in any drug development program and are often the gate-keeper for large confirmatory studies. In this overview paper we focus on definitive and confirmatory dose finding studies in Phase II or III, reviewing relevant statistical design and analysis methods. In particular, we describe multiple comparison procedures, modeling approaches, and hybrid methods combining the advantages of both. An outlook to adaptive dose finding methods is also given. We use a real data example to illustrate the methods, together with a brief overview of relevant software.     

Behavior,Ecology, and Demography of <Emphasis Type="Italic">Aotus vociferans</Emphasis> in Yasuní National Park,Ecuador

Given its broad geographical distribution, Aotus is a productive genus for comparative studies that evaluate how different ecological factors influence the morphology, behavior, ecology, and demography of closely related species. During 18 mo we collected demographic, ranging, and activity data from owl monkeys (Aotus vociferans) in Yasuní National Park in eastern Ecuador. To collect demographic data, we monitored the trail system several times per week searching for groups. To characterize patterns of activity, we recorded the time when the subjects began and ended their nocturnal activity, and we collected data on range use and daily path length during 12 full-moon and 12 new-moon night follows of 1 radiocollared group. They ranged in size between 3 and 5 individuals (n = 4 groups). All groups were strictly nocturnal, beginning their activity between 1800 and 1900 h and finishing it between 0500 and 0600 h. The territory size of the radiocollared group was 6.3 ha. On average, the subjects traveled 645 m per night (±286 m) and ranged farther during full-moon than new-moon nights. The owl monkeys used a small number of preferred daytime sleeping trees. Our data conform well with previous studies of other tropical owl monkeys from Colombia and Perú. A comparison of tropical owl monkeys with more temperate Aotus azarai from the Argentinean Gran Chaco reveals that grouping patterns, day range length, and territory size are relatively conserved across the genus despite dramatic differences in body size and activity pattern.     

Habitat Exploitation by Free-ranging Saguinus niger in Eastern Amazonia

We monitored the foraging behavior of the members of a group of black-handed tamarins (Saguinus niger) at a site in eastern Amazonia. Their diet was frugivorous-insectivorous, but also included pod exudate of Parkia pendula. The focal group used all 3 types of forest—primary, logged, and secondary— in all months, but differentially between seasons. In the dry season, tamarins spent more than half of activity time in primary forest and less than a third in secondary forest whereas during the wet season, the proportions were reversed. Data on resource abundance indicated that the shift in habitat preference is related to a seasonal change in the distribution of fruit sources, with a larger number of species and individuals fruiting during the wet season. We recorded no such variation in the abundance of arthropods. While using a larger area, including more secondary forest, during the wet season, the group traveled significantly shorter distances each day, reflecting the availability of a larger number of fruit sources. Overall, the results reemphasize the ecological and behavioral flexibility of Saguinus niger and their ability to cope with habitat disturbance.     

Effects of a Typhoon on Foraging Behavior and Foraging Success of <Emphasis Type="Italic">Macaca fuscata</Emphasis> on Kinkazan Island,Northern Japan

We studied the effects of typhoon damage on the food habits, time budgets, and moving distances of Japanese macaques (Macaca fuscata) on Kinkazan Island, northern Japan. Before the typhoon (pre-typhoon phase), the macaques fed on various food items, including fruit in trees (Swida macrophylla) and nuts (Torreya nucifera) on the ground. After the typhoon passed (post-typhoon phase), the macaques fed intensively on the seeds of Perilla frutescens (a forb) and the nuts of Quercus serrata on the ground. One may attribute the changes to decreased food availability or foraging efficiency of fruits and nuts on the ground, due to their concealment by leaf litter and mud and their consumption by other animals, such as sika deer (Cervus nippon) and field mice (Apodemus argenteus). In the post-typhoon phase, the macaques fed more quickly on seeds of Perilla frutescens, spent less time traveling, and moved over shorter distances. The differences may be due to changes in the distribution of staple foods between the 2 phases. We also evaluated the energy intake and energy balance of the macaques in both phases, based on observations of foraging and nutritional analyses of the food items. There is no significant difference in either parameter between the 2 phases. The changes in food habits and movement behavior may have compensated for the reduced food availability or foraging efficiency caused by the typhoon. Both behavioral changes and nutritional issues are important when investigating the effects of storms on animal ecology.     

Ten days in the life of a mandrill horde in the Lopé Reserve,Gabon

Mandrills have long been known to form large aggregations in the wild, but it has proved difficult to obtain detailed information on the socioecology of these groups. An unusually large (>600) horde of mandrills was followed for ten days during the 1995 dry season in Central Gabon, and data were collected on group composition and ecology while the mandrills were in an area of forest-savanna mosaic habitat in the north of the Lopé Reserve. Three separate counts of most of the group showed that fully coloured “fatted” adult males were present throughout the horde at a mean ratio to other individuals of 1:21. Paler “non-fatted” adult and sub-adult males were also distributed throughout. Mandrill diet over the ten days consisted mainly of insects, seeds from forest trees, and leaves or stems of understory herbaceous plants. Feeding was extremely selective, with most food items consumed in a much higher proportion than would be predicted from their relative availability. Ranging data also showed that the mandrills foraged preferentially in certain forest types within the forest-savanna mosaic, namely in Marantaceae and Rocky Forest. It is suggested that one reason why mandrills pass through gallery forests and forest-savanna mosaic in the dry season in the Lopé Reserve is because they find fruit there from preferred species, which are no longer fruiting in the main forest block, thus allowing them to maintain the fruit component of their diet at a time of fruit shortage. © 1996 Wiley-Liss, Inc.