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Nocturnal Species (nocturnal + species)
Selected AbstractsThe Importance of Visual Cues for Nocturnal Species: Eagle Owl Fledglings Signal with White Mouth FeathersETHOLOGY, Issue 10 2007Vincenzo Penteriani Complex begging display by bird offspring has predominantly been investigated in diurnal species, which have conspicuous gape colours or plumage features. In nocturnal species, in contrast, such visual communication has received little attention because the assumption is that they exclusively rely on vocal communication. Here, we use a field experiment to investigate whether eagle owls, Bubo bubo, communicate through visual signals at night. We artificially decreased the brightness of the white feathers surrounding fledgling eagle owls' mouths during the post-fledging dependence period, and investigated the effect of this treatment by comparing the condition of these birds to that of birds who received a control treatment. Several physiological parameters considered in our analyses indicate that control owlets were in better condition than owlets with brightness-reduced mouth feathers, which suggests that they received more or better food from feeding parents who discriminated between those young. Brightness-dependent reactions of parent owls suggest that visual signalling may be more widely employed than previously thought, and studying birds at night may reveal sophisticated strategies of animal communication. [source] Ecological niche modelling as a technique for assessing threats and setting conservation priorities for Asian slow lorises (Primates: Nycticebus)DIVERSITY AND DISTRIBUTIONS, Issue 2 2009J. S. Thorn ABSTRACT Aim, Data on geographical ranges are essential when defining the conservation status of a species, and in evaluating levels of human disturbance. Where locality data are deficient, presence-only ecological niche modelling (ENM) can provide insights into a species' potential distribution, and can aid in conservation planning. Presence-only ENM is especially important for rare, cryptic and nocturnal species, where absence is difficult to define. Here we applied ENM to carry out an anthropogenic risk assessment and set conservation priorities for three threatened species of Asian slow loris (Primates: Nycticebus). Location, Borneo, Java and Sumatra, Southeast Asia. Methods, Distribution models were built using maximum entropy (MaxEnt) ENM. We input 20 environmental variables comprising temperature, precipitation and altitude, along with species locality data. We clipped predicted distributions to forest cover and altitudinal data to generate remnant distributions. These were then applied to protected area (PA) and human land-use data, using specific criteria to define low-, medium- or high-risk areas. These data were analysed to pinpoint priority study sites, suitable reintroduction zones and protected area extensions. Results, A jackknife validation method indicated highly significant models for all three species with small sample sizes (n = 10 to 23 occurrences). The distribution models represented high habitat suitability within each species' geographical range. High-risk areas were most prevalent for the Javan slow loris (Nycticebus javanicus) on Java, with the highest proportion of low-risk areas for the Bornean slow loris (N. menagensis) on Borneo. Eighteen PA extensions and 23 priority survey sites were identified across the study region. Main conclusions, Discriminating areas of high habitat suitability lays the foundations for planning field studies and conservation initiatives. This study highlights potential reintroduction zones that will minimize anthropogenic threats to animals that are released. These data reiterate the conclusion of previous research, showing MaxEnt is a viable technique for modelling species distributions with small sample sizes. [source] The Importance of Visual Cues for Nocturnal Species: Eagle Owl Fledglings Signal with White Mouth FeathersETHOLOGY, Issue 10 2007Vincenzo Penteriani Complex begging display by bird offspring has predominantly been investigated in diurnal species, which have conspicuous gape colours or plumage features. In nocturnal species, in contrast, such visual communication has received little attention because the assumption is that they exclusively rely on vocal communication. Here, we use a field experiment to investigate whether eagle owls, Bubo bubo, communicate through visual signals at night. We artificially decreased the brightness of the white feathers surrounding fledgling eagle owls' mouths during the post-fledging dependence period, and investigated the effect of this treatment by comparing the condition of these birds to that of birds who received a control treatment. Several physiological parameters considered in our analyses indicate that control owlets were in better condition than owlets with brightness-reduced mouth feathers, which suggests that they received more or better food from feeding parents who discriminated between those young. Brightness-dependent reactions of parent owls suggest that visual signalling may be more widely employed than previously thought, and studying birds at night may reveal sophisticated strategies of animal communication. [source] Dietary specialization and climatic-linked variations in extant populations of Ethiopian wolvesAFRICAN JOURNAL OF ECOLOGY, Issue 2 2010Jorgelina Marino Abstract Understanding of the biology of rarity is central to the conservation of some endangered species. Rare taxa are often reported to be specialized, but they are usually poorly studied. The Ethiopian wolf (Canis simensis) is endemic to the Ethiopian highlands and in two major populations, Bale and Arsi in the southern range of the species, it preys almost exclusively upon diurnal rodents all year round, mainly molerats Tachyoryctes macrocephalus and common molerats T. splendens, respectively. Where these large rodents are absent or rare, wolves are expected to rely more heavily on nocturnal rats or livestock. Prey remains in 161 scats from five newly studied populations confirmed that wolves are indeed specialist rodent hunters elsewhere, and that their narrow diets are dominated by diurnal Murinae rats (60,83% of prey occurrences). Swamp rats Otomys typus were the main prey, followed by grass rats Arvicanthis abyssinicus. Common molerats, Lophuromys rats and nocturnal Stenocephalemys spp. constituted the variable portion of the diets, and their proportional contributions varied across populations in relation to elevation and latitude. Towards the north, where the climate is drier and human populations more dense, wolves predate more frequently on rat-sized prey, including nocturnal species, with implications for the survival of small populations in the Northern Highlands. Résumé Pour la conservation de certaines espèces en danger, il est essentiel de bien comprendre la biologie de la rareté. On rapporte souvent que des taxons rares sont spécialisés, mais ils sont généralement peu étudiés. Le loup d'Ethiopie Canis simensis est endémique des hauts plateaux éthiopiens et deux populations majeures, Bale et Arsi, dans la partie sud de leur aire de répartition, se nourrissent toute l'année presque exclusivement de petits rongeurs diurnes, surtout des rats-taupes géants Tachyoryctes macrocephalus et, plus communs, des rats taupes des montagnes T. splendens. Là où ces rongeurs sont absents ou rares, on s'attend à ce que les loups se nourrissent davantage de rats nocturnes ou de bétail. Des restes de proies identifiées dans 161 crottes de cinq nouvelles populations étudiées récemment ont confirmé que les loups sont bien, ailleurs, des chasseurs spécialisés en rongeurs et que leur régime alimentaire peu varié est dominé par des Murinae diurnes (60,83% des proies observées). Les rats des marais Otomys typusétaient les proies principales, suivis par les rats des herbes Arvicanthis abyssinicus. Les rats-taupes communs, les rats Lophuromys et les nocturnes Stenocephalemys spp. constituaient des portions variables du menu, et la proportion de leur contribution variait pour les populations en fonction de l'elevation et de la latitude. Vers le nord, là où le climat est plus sec et où la population humaine est plus dense, les loups s'attaquent plus souvent à des proies de la taille des rats, y compris des espèces nocturnes, ce qui a des implications pour la survie des petites populations des hauts plateaux du nord. [source] Divided and undivided compound eyes in Ascalaphidae (Insecta, Neuroptera) and their functional and phylogenetic significanceJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 4 2006K. Fischer Abstract The external morphology of the compound eyes of 13 species of the Ascalaphidae family (Insecta, Neuroptera) from Africa, Asia and Europe was studied in relation to the habitat, phylogeny and time of activity during the day. The six species with undivided eyes (Haplogleniinae) are nocturnal; four inhabit more or less open terrain, while two inhabit more or less dense vegetation. Of the seven species with divided eyes (Ascalaphinae), three are diurnal, one is crepuscular and nocturnal, and three are nocturnal. It was found that two of the diurnal species inhabit open terrain and open forest, and one inhabits dense vegetation; the crepuscular and nocturnal species inhabits open terrain; and two of the nocturnal species inhabit open terrain, while one inhabits dense vegetation. The results are discussed in relation to the hypothesis that divided eyes evolved from undivided eyes, originally serving as an adaptation to daytime vision in open terrain. Zusammenfassung Bei 13 Arten aus der Familie der Ascalaphidae (Insecta, Neuroptera) aus Afrika, Asien und Europa wurde die externe Morphologie der Komplexaugen im Zusammenhang mit der tageszeitlichen Aktivität, dem Habitat und der Phylogenie untersucht. Alle sechs Arten mit ungeteilten Augen (Haplogleniinae) sind nachtaktiv. Vier kommen im mehr oder weniger offenen Gelände und zwei kommen in mehr oder weniger dichter Vegetation vor. Von den sieben Arten mit geteilten Augen (Ascalaphinae) sind drei tagaktiv, eine ist dämmerungs- und nachtaktiv und drei sind nachtaktiv. Zwei von den tagaktiven Arten kommen im offenen Gelände und in lichten Baumbeständen vor, eine Art bewohnt dichte Vegetation. Die dämmerungs- und nachtaktive Art kommt im offenen Gelände vor.Von den drei nachtaktiven Arten kommen zwei im offenen Gelände vor, eine bevorzugt dichte Vegetation. Die Ergebnisse werden im Zusammenhang mit der Hypothese diskutiert, dass sich im Verlauf der Evolution die geteilten Augen aus ungeteilten Augen entwickelt haben und ursprünglich eine Anpassung an das Sehen bei Tag im offenen Gelände darstellen. [source] Assessing reproductive profiles in female brown mouse lemurs (Microcebus rufus) from Ranomafana National Park, southeast Madagascar, using fecal hormone analysisAMERICAN JOURNAL OF PRIMATOLOGY, Issue 6 2009Marina B. Blanco Abstract Studies on reproductive endocrinology in wild primate populations have greatly increased in the last decades owing to the development of noninvasive techniques that can be applied under field conditions. However, small-bodied nocturnal species are not well represented on the long list of primates surveyed in the wild, and reproductive inferences regarding these animals in their natural habitats have not benefited from direct observations of hormonal changes. We collected fecal samples from female brown mouse lemurs (Microcebus rufus) in a southeastern rainforest of Madagascar in order to determine whether or not fecally excreted steroid levels show a consistent pattern of change during the reproductive season and are a useful complement to reproductive observations in wild-trapped individuals. Initial data show variation in reproductive hormone levels before and after estrus and estimated day of parturition. Elevated levels of excreted estradiol (E2) were observed around the time of estrus, whereas high levels of fecal progesterone (P) were seen during later stages of pregnancy and around parturition. A more complete picture of reproductive profiles in female mouse lemurs, and how they may change over the life span, can be obtained if hormone analyses are used to supplement field observations. Am. J. Primatol. 71:439,446, 2009. © 2009 Wiley-Liss, Inc. [source] Mutational changes in S-cone opsin genes common to both nocturnal and cathemeral Aotus monkeysAMERICAN JOURNAL OF PRIMATOLOGY, Issue 7 2007David H. Levenson Abstract Aotus is a platyrrhine primate that has been classically considered to be nocturnal. Earlier research revealed that this animal lacks a color vision capacity because, unlike all other platyrrhine monkeys, Aotus has a defect in the opsin gene that is required to produce short-wavelength sensitive (S) cone photopigment. Consequently, Aotus retains only a single type of cone photopigment. Other mammals have since been found to show similar losses and it has often been speculated that such change is in some fashion tied to nocturnality. Although most species of Aotus are indeed nocturnal, recent observations show that Aotus azarai, an owl monkey species native to portions of Argentina and Paraguay, displays a cathemeral activity pattern being active during daylight hours as frequently as during nighttime hours. We have sequenced portions of the S-cone opsin gene in A. azarai and Aotus nancymaae, the latter a typically nocturnal species. The S-cone opsin genes in both species contain the same fatal defects earlier detected for Aotus trivirgatus. On the basis of the phylogenetic relationships of these three species these results imply that Aotus must have lost a capacity for color vision early in its history and they also suggest that the absence of color vision is not compulsively linked to a nocturnal lifestyle. Am. J. Primatol. 69:757,765, 2007. © 2007 Wiley-Liss, Inc. [source] Avoiding predators at night: antipredator strategies in red-tailed sportive lemurs (Lepilemur ruficaudatus)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 6 2007Claudia Fichtel Abstract Although about one-third of all primate species are nocturnal, their antipredator behavior has rarely been studied directly. Crypsis and a solitary lifestyle have traditionally been considered to be the main adaptive antipredator strategies of nocturnal primates. However, a number of recent studies have revealed that nocturnal primates are not as cryptic and solitary as previously suggested. Thus, the antipredator strategies available for diurnal primates that rely on early detection and warning of approaching predators may also be available to nocturnal species. In order to shed additional light on the antipredator strategies of nocturnal primates, I studied pair-living red-tailed sportive lemurs (Lepilemur ruficaudatus) in Western Madagascar. In an experimental field study I exposed adult sportive lemurs that lived in pairs and had offspring to playbacks of vocalizations of their main aerial and terrestrial predators, as well as to their own mobbing calls (barks) given in response to disturbances at their tree holes. I documented the subjects' immediate behavioral responses, including alarm calls, during the first minute following a playback. The sportive lemurs did not give alarm calls in response to predator call playbacks or to playbacks with barks. Other behavioral responses, such as gaze and escape directions, corresponded to the hunting strategies of the two classes of predators, suggesting that the corresponding vocalizations were correctly categorized. In response to barks, they scanned the ground and fled. Because barks do not indicate any specific threats, they are presumably general alarm calls. Thus, sportive lemurs do not rely on early warning of acoustically simulated predators; rather, they show adaptive escape strategies and use general alarm calls that are primarily directed toward the predator but may also serve to warn kin and pair-partners. Am. J. Primatol. 69:611,624, 2007. © 2007 Wiley-Liss, Inc. [source] Summer activity patterns of nocturnal Scarabaeoidea (Coleoptera) of the southern tablelands of New South WalesAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 1 2007Martin J Steinbauer Abstract, Australia has a rich diversity of Scarabaeoidea; however, little is known about the majority of them. Because adults of Anoplognathus, Automolius, Heteronychus, Heteronyx and Liparetrus in particular are reliant upon eucalypts, a number of bluegum plantation companies supported the commencement of research into the biology and ecology of scarabs of economic significance to them. Consequently, it was decided that the occurrences of species endemic to this area would be studied and it was assumed that information on the nocturnal species in the aforementioned genera would be obtained. From late November 2003 until late February 2004, the abundances of Scarabaeoidea caught in two light traps that partition insects caught on a given night into seven time periods each of 1.75 h duration were recorded. A total of 48 263 scarabs representing 21 genera were caught. Within the 14 species caught most often, six types of summer activity pattern were apparent: late spring to early summer (Australobolbus gayndahensis), early to mid-summer (Scitala sericans), mid-summer only (Sericesthis ignota), mid- to late summer (Acrossidius tasmaniae, Aphodius lividus, Heteronyx chlorotica, Het. praecox and Antitrogus morbillosus), late summer only (Ataenius picinus) and all summer (Anoplognathus pallidicollis, Phyllotocus macleayi, Sericesthis geminata, Ser. micans and Ser. nigrolineata). Abundances of nine species peaked between 21:30 and 23:15 h (Aph. lividus, Phy. macleayi, Het. chlorotica, Sci. sericans, Ser. geminata, Ser. micans, Ser. nigrolineata and possibly also Ant. morbillosus), three were most abundant between 19:45 and 21:30 h (Ano. pallidicollis, Ser. ignota and possibly also Ata. picinus), another two were most abundant from 19:45 to 23:15 h (Acr. tasmaniae and Het. praecox) and Aus. gayndahensis was most abundant between 23:15 and 01:00 h. Of course, it is not just a knowledge of the identity of the species and the timing of their occurrence that are important when making insect management decisions, but also the size of population needed to inflict economically significant loss. It is now beholden upon bluegum plantation companies to support further research to determine the relationships between light trap catches of eucalypt-feeding scarabs, tree age and/or size and level of defoliation in order to improve their confidence in this method of monitoring over ground surveys. [source] | ||||||||||