Browse results

You are looking at 1 - 100 of 12,167 items for :

  • Biology & Environmental Sciences x
Clear All
Dorylaims are probably the most diverse order of nematodes and are often an abundant component of the fauna in soils and freshwater habitats. As a result of their widespread distribution and many different feeding habits, they are considered as good bio-indicators of environmental quality and soil health. Their usefulness in this regard is only impeded by practical difficulties related to the accurate identification of the members of such a large and complex group. In this volume, Professor Reyes Peña-Santiago gives a detailed morphology of the dorylaims and provides a thorough overview of their feeding behaviour, reproduction, ecology, and diversity. You will learn what dorylaims are like and how they live, making this book an invaluable tool for nematologists, ecologists and other scientists who wish to embark on an in-depth study of the members of this fascinating group.

Species boundaries delineating tropical sea anemones (Cnidaria, Actiniaria) of the zooxanthellate genus, Heteranthus , are unclear. There are currently two valid Heteranthus species: type species Heteranthus verruculatus , first reported from Koseir, Egypt, and H. insignis , from Poulo Condore, Vietnam. In describing the latter from a single, poorly preserved specimen, zoologist Oskar Carlgren expressed apprehension with traits he had used to establish this species. Carlgren’s doubts persisted later in writing when he found a similar-looking sea anemone from the Great Barrier Reef. Crucial details to positively identify either species have since remained limited. Here, we re-diagnosed Heteranthus and re-described its type species based on observations of specimens we have obtained from Singapore and Pulau Ambon (Indonesia), and of museum material collected elsewhere across the Indo-West Pacific region (n > 180). Supported by molecular phylogenetic evidence, the family Heteranthidae was reinstated and re-diagnosed. Heteranthus verruculatus is encountered in the lower intertidal region amongst seagrass, in rocky crevices, or coral rubble. It occurs as solitary individuals or in clonal clusters, well-camouflaged against the substratum. Individuals were observed to frequently propagate by longitudinal fission, resulting in a varied appearance. Type material of H. verruculatus and H. insignis were re-examined and as we found no differences between them, the two were synonymised. We inferred that Carlgren probably misinterpreted cnidae and histological data in defining H. insignis as a distinct species. This revision clarifies the taxonomy and geographic range of H. verruculatus, an Indo-West Pacific species that is found from the Red Sea to subtropical Australia and Hawaii.

In: Contributions to Zoology

Northwest African material previously ascribed to the subspecies Nephrotoma guestfalica surcoufi (Pierre, 1925) proved to belong to two distinct morphological forms, the true N. g. surcoufi from Algeria, and Tunisia, and the here newly introduced Nephrotoma guestfalica vaillanti n. subsp. from Morocco. With the distinction of the new form, four subspecies of Nephrotoma guestfalica (Westhoff, 1879) are now recognized, all occurring in the western Palaearctic. An identification key for the males of the four taxa of Nephrotoma guestfalica s.l. is provided. The male terminalia of the four taxa are illustrated. The distribution of the four subspecies is summarized, based on material examined and published data. A map showing the currently known distribution of N. guestfalica surcoufi and N. guestfalica vaillanti is presented. Nephrotoma guestfalica guestfalica is recorded here for the first time from Croatia.

In: Tijdschrift voor Entomologie

Abstract

Environmental temperatures often regulate the activity and physiological processes of ectotherms. Because environmental temperatures can vary significantly among seasons, lizards exposed to different thermal conditions in different months could differ in how they thermoregulate or behave. Here, we present a combination of field, laboratory, and modeling approaches to examine thermoregulation, habitat thermal quality, and hours of thermal restriction on activity in a saxicolous population of Urosaurus ornatus in two thermally contrasting months (June and October) in a micro-insular mountain system in the northern Chihuahuan Desert in Mexico. Both active and preferred body temperatures did not vary between months. In this population, U. ornatus is an active thermoregulator with highly accurate and efficient thermoregulation despite the thermal quality in both months. However, during the breeding season (June) activity is restricted (i.e., high number of hours of restriction) compared to the non-breeding season (October). Therefore, our results suggest that this saxicolous population of U. ornatus could be threatened by global climate change and it is essential to determine a conservation strategy for this population.

In: Amphibia-Reptilia

Two new Elmidae species from the Visayan island of Negros, Philippines, Ancyronyx berghaueri sp. n. and Ancyronyx negrosensis sp. n., are described utilizing an integrative taxonomic approach. The new species are characterized by the color of the femora, body size, and the male and female genitalia. Their habitus and diagnostic characters are described and illustrated in detail with microscopic images and digital line drawings. The morphological species delimitation is supplemented by and congruent with COI and cob mtDNA data of several known species of Ancyronyx from the Philippines and Borneo. The material was obtained in connection with a student thesis, the sampling program of the Ateneo de Manila University Biodiversity Laboratory and from repositories. Specimens were collected at altitudes between 30 m and 800 m above sea level in pristine and slightly disturbed habitats. Their suitability as bioindicators and the use of cob sequences for integrative taxonomic studies are briefly discussed. (ZooBank registration: http://zoobank.org/DE45871B-538D-4C5A-80C1-6FCA0CCC4860)

In: Tijdschrift voor Entomologie

Abstract

Group-living animals can potentially enhance their foraging performance and efficiency by obtaining information from others. Using PIT-tag data to study foraging behaviour in individual bats, we tested short-tailed fruit bats, Carollia perspicillata (Linnaeus), for evidence of local enhancement or social facilitation. To discriminate between these phenomena, we manipulated the presence of conspecifics while individuals searched for food. We quantified the time to find food and the order and sex of bats accessing the food, and any consistent associations between bats. Presence of conspecifics decreased the time needed to find food. We found no evidence that pairs of individuals consistently fed together; however, bats of the same sex tended to feed closer in time with one another. The same individuals consistently accessed the food first, and males found food more quickly than females. Our results provide evidence of social facilitation, with bats finding food more quickly in a group than alone.

In: Behaviour

Abstract

The efficacy of animal acoustic communication depends on signal transmission through an oft-cluttered environment. Anthropogenic-induced changes in vegetation may affect sound propagation and thus habitat quality, but few studies have explored this hypothesis. In the southwestern United States, fire suppression and cattle grazing have facilitated displacement of grasslands by pinyon-juniper woodlands. Northern grasshopper mice (Onychomys leucogaster) inhabit regions impacted by juniper encroachment and produce long-distance vocalizations to advertise their presence to conspecifics. In this study, we coupled acoustic recordings and electrophysiological measurements of hearing sensitivity from wild mice in the laboratory with sound transmission experiments of synthesized calls in the field to estimate the active space (maximum distance that stimuli are detected) of grasshopper mouse vocalizations. We found that mice can detect loud (85 dB SPL at 1 m) 11.6 kHz vocalizations at 28 dB SPL. Sound transmission experiments revealed that signal active space is approximately 50 m. However, we found no effect of woody plant encroachment on call propagation because juniper and woody plant density were inversely associated and both present barriers to a 9 cm mouse advertising at ground level. Our data indicate that woody plant encroachment does not directly impact the efficacy of grasshopper mouse communication, but vegetation shifts may negatively impact mice via alternative mechanisms. Identifying the maximum distance that vocalizations function provides an important metric to understand the ecological context of species-specific signalling and potential responses to environmental change.

In: Behaviour

Abstract

Although most male frogs call to attract females, vocalizations alone can be ineffective long-range signals in certain environments. To increase conspicuousness and counter the background noise generated by rushing water, a few frog species around the world have evolved visual communication modalities in addition to advertisement calls. These species belong to different families on different continents: a clear example of behavioural convergent evolution. Until now, long-distance visual signalling has not been recorded for any species in the glassfrog family (Centrolenidae). Sachatamia orejuela, an exceptionally camouflaged glassfrog species found within the spray zone of waterfalls, has remained poorly studied. Here, we document its advertisement call for the first time — the frequency of which is higher than perhaps any other glassfrog species, likely an evolutionary response to its disruptive acoustic space — as well as a sequence of non-antagonistic visual signals (foot-flagging, hand-waving, and head-bobbing) that we observed at night.

In: Behaviour

Abstract

Gibbons (family Hylobatidae) are renowned for their melodious territorial songs but other aspects of their acoustic communication have received little research attention. Here we describe an apparently novel idiosyncratic non-song vocalization in an adult captive Southern white-cheeked gibbon (Nomascus siki), which we suggest acts specifically in attracting a human’s attention. For this preliminary report we analysed 25 individual calls recorded over a period of 6 months. Typically, calling is accompanied by clapping and feet-slapping, behaviours not reported from gibbons in comparable situations so far. The utilization of both innovative vocalizations and other acoustic displays as human-directed attention getters, reminiscent of our white-cheeked gibbon subject, is known from great apes, which further suggests a concordant behavioural function. However, the gibbon’s displays, despite their unequivocal novelty, could also represent unintentional behavioural responses related to frustration. Eventually, experimental approaches are required to clarify what underlies this unusual behaviour.

In: Behaviour

Abstract

Exploring the mechanisms that affect mating pattern with respect to body size has implications for understanding the evolution of sexual selection. Theory predicts that the absence of a relationship between female body size and fecundity, unbiased operational sex ratio, and a short breeding season will lead to random mating by body size in anuran amphibians. We tested these predictions in the Himalayan toad Duttaphrynus himalayanus inhabiting southeastern Tibet. Our study did not detect any correlation between female body size and number of eggs laid, nor was there a significant difference in the sex ratio of toads captured from the breeding site. In addition, the toads were reproductive for only a short period, from late April to early May (typical of an explosively breeding species). As expected, we detected a weak but not significant relationship between body size of amplexing males and females. Our results revealed no apparent size-assortative pairing in the study population of the Himalayan toad and may contribute to an increasing body of literature on mating patterns in relation to body size in animals with indeterminate growth.

In: Animal Biology
In: Amphibia-Reptilia

We here transfer an euptychiine taxon hitherto placed in the polyphyletic genus Magneuptychia Forster, 1964, to Caeruleuptychia Forster, 1964. Caeruleuptychia francisca (Butler, 1870), n. comb. is reclassified based on a morphology-based maximum likelihood analysis, which is consistent with ongoing analyses of molecular data. Two putative synapomorphic characters are identified for the “Caeruleuptychia umbrosa clade”, one of which appears to be an unusual characteristic of euptychiine butterflies and is tested by optimizing onto the maximum likelihood tree. We also discuss the systematic placement of three additional enigmatic Caeruleuptychia species. A lectotype is designated for Euptychia francisca, and the genitalia of this species are illustrated here for the first time.

In: Tijdschrift voor Entomologie

Abstract

Among the most damaging anthropogenic effects for ecosystems is habitat fragmentation. One of its consequences is the creation of edges, which results in more exposed habitats that have different ecological and behavioural effects on the different species that live there. However, the nature and magnitude of these effects remain unknown for most of the animals and plants inhabiting these edge habitats. This study intends to determine if quantity of prey capture by a woodland population of the orb spider Metellina mengei is subjected to edge effects. By observing the prey capture of this species at edge and interior locations of a woodland, we found no significant effects of edge on the number of prey captured or the average prey length. Instead, we found that inclination of the web, but not web area or other measured web parameters, had a significant effect on prey capture. Therefore, this species of spider may be minimally affected by its location within the woodland and more affected by its surrounding microhabitat, which raises the possibility that non-specialised invertebrate predators could be less impacted by fragmentation than generally recognised.

In: Animal Biology

Abstract

Scent-marking is a predominant form of communication among felids, with urine spraying having a key role. Detectability and longevity of scent marks are recognized as crucial for efficiency of scent-marking, but there is limited research that has tested scent persistence with respect to various environmental factors. We used an experimental framework to measure human-perceived strength of felid urine smell and determine the effects of substrate, tilt and aspect of marked surfaces on persistence of the simulated scent marks. We used area under the curve (AUC), calculated for the scent strength of each scent-marked surface over time, as a proxy for urine scent preservation. Thereafter, we used ANOVA, followed by analysis of differences of interest between the marking sites, to assess the effect of environmental factors on human-perceived scent mark persistence. Odour persisted significantly better on rough surfaces, surfaces covered with moss and on surfaces with overhanging tilts, while there was no significant difference between the northerly- and southerly-oriented surfaces. The results are generally in accordance with the use and selection of marking sites previously reported for wild felids throughout the world, confirming that in their marking behaviour felids strive to prolong the persistence of scent marks. This knowledge will help researchers in interpretation of data on scent-marking and to evaluate the adaptive significance of this behaviour.

In: Animal Biology

Hyadina borkumensis sp. n. is described from the East Frisian Island of Borkum (Germany, Lower Saxony, Wadden Sea) based on a single female specimen. The new species is characterized by the basally bent, brown wings with large white spots in radial cells r2+3, r4+5 and apical of crossvein dm-cu and its short radial vein R2+3. The new species shares the lateroclinate fronto-orbital seta with representatives of the Australasian–Oceanian genus Parahyadina Tonnoir & Malloch, 1926. The implication of this shared character for the use of relevant Ephydridae keys is briefly discussed. (ZooBank registration: http://zoobank.org/C354B2BB-0E8A-4D31-A869-9753474DB50B).

In: Tijdschrift voor Entomologie

The geminia and semiobsoleta groups of the genus Cyphura (Lepidoptera: Uraniidae) are revised. Five new species are described. There are four new species in the geminia species group: Cyphura pallidata sp. n., C. marcoi sp. n., C. aruensis sp. n., and C. numforensis sp. n. In this group, a lectotype is designated for Strophidia costalis , C. subsimilis , S. bifasciata , C. catenulata , Urapteroides approximans , U. falka , U. swinhoei and for U. swinhoei . Six new synonyms are proposed: U. gutturalis () is a junior synonym of C. geminia (), C. subsimilis is a junior synonym of C. costalis (), C. catenulata and U. approximans () are both junior synonyms of C. bifasciata (), U. falka () is a junior synonym of C. pieridaria and U. swinhoei () is a junior synonym of C. maxima (). Urapteroides swinhoei is transferred to Cyphura as Cyphura swinhoei () comb. n.

In the semiobsoleta species group, one new species is described: C. trifasciata sp. n. In this group a lectotype is designated for Urapteroides semiobsoleta , U. semiobsoleta reducta , C. multistrigaria and for C. multistrigaria ab. dealbata .

In: Tijdschrift voor Entomologie

Abstract

The Atlas day gecko, Quedenfeldtia moerens, a Moroccan endemic lizard, is strictly diurnal and widely distributed across the dry Atlas Mountains. We quantified thermoregulation in adult males and adult females during their active season in the L’kest Mountain at 1300 m a.s.l., Anti-Atlas region of Morocco. The operative temperatures and air temperatures were sampled using data-loggers in the field from 2016 to 2018. Body temperatures of active lizards and substrate temperatures in the field were simultaneously measured. Finally, we measured preferred body temperatures (Tset) in a laboratory thermal gradient for 24 adult geckos. Mean Tset was 33.3 ± 0.3°C, with the mean 25% and 75% quartiles being 32.3 ± 0.3°C and 34.6 ± 0.3°C, respectively. Active lizards rarely reached their Tset range from March to June, but spent most of the day within Tset in July and August. Our study suggests that Q. moerens have higher Tset than its congeneric Q. trachyblepharus living at high altitude. Likewise, thermoregulatory effectiveness of Q. moerens showed an increase from spring to summer while it was the opposite for Q. trachyblepharus.

In: Amphibia-Reptilia

Abstract

We investigated age structure, age at sexual maturity, lifespan, growth and survival rate and adult life expectancy (as demographic life-history traits) as well as body size of two Darevskia derjugini (Artvin lizard) populations from different altitudes, using skeletochronology. Our findings indicated that age upon attaining sexual maturity was two or three years in the low-altitude population (Fındıklı) while it was three years in the high-altitude population (Murgul) for both sexes. The maximum longevity was seven years in the high-elevation site while it was six years in the low-elevation site. As reported for many lizards, we found a significant positive relationship between age and body size within each sex of Artvin lizard at both altitudes. High- and low-altitude populations did not differ in age structure, survival rates, adult life expectancy and body size. Rather than the effect of altitude, which is hard to compare without replication of other low and high altitude populations, the fact that these two populations have similar growth rates and the similarity of local conditions (food availability and predator density) may indicate similarity between the two regions.

In: Animal Biology

Abstract

The status of Eremias stummeri in China has been a matter of controversy for over two decades, although it is well acknowledged that this species occurs in Northeast Kyrgyzstan and Southeast Kazakhstan. To date, whether its occurrence extends to the adjacent Chinese region (possibly in the Ily River Valley) has not been confirmed yet. To overcome constraints on field surveys imposed by the region’s remoteness and rugged terrain, we targeted areas of further field inventories by estimating the potential distribution of the species. Ecological niche modeling (ENM) enabled us to predict a continuous distribution area from Kazakhstan to the Chinese part of the Ily River Valley in Zhaosu county for the species’ occurrence. We conducted extensive field surveys in the predicted area. In 2017, for the first time, the occurrence of E. stummeri in China was confirmed with a single find in Zhaosu county. Further morphological and multilocus phylogenetic analyses congruently supported the taxonomic status of the recently discovered population as E. stummeri. In contrast to its distribution continuity between Kazakhstan and China, the ENM indicates distribution discontinuity between Kazakhstan and Kyrgyzstan. This geographic distribution pattern of E. stummeri is supported by morphological and molecular evidence, which highlights that individuals from China and Kazakhstan are more closely related to each other than to those from Kyrgyzstan. The mismatch between mitochondrial and nuclear phylogeographic pattern implies that historical mitochondrial introgression occurred from E. stummeri individuals from Kyrgyzstan to those from Kazakhstan.

In: Amphibia-Reptilia

Abstract

The processes underlying macroecological gradients in body size are widely debated, in part because their intraspecific variability remains poorly described even in well-studied taxa such as vertebrates. In this study, we investigated how climate, habitat, genetic lineage and sex explain body size variations in French populations of the European pond turtle (Emys orbicularis). We measured 7016 adult individuals captured in 41 populations, covering most of the species’ distribution in metropolitan France, including Corsica. Body size variation in our sample was wide and comparable to that found across the species’ worldwide range. Variation was similar in magnitude at regional and local levels, suggesting that body size is influenced by local factors as much as by regional factors such as climate or genetic lineage. Smaller sizes were associated with Mediterranean or altered oceanic climates, and with two lineages (E. o. galloitalica and E. o. galloitalica/E. o. orbicularis), while larger sizes were associated with northern environments and the orbicularis lineage. Body size variations recorded at local level reflect an adaptive response to environmental constraints, suggesting that habitat is also an important factor in understanding size variation.

In: Amphibia-Reptilia

Abstract

Under extreme environmental conditions such as hypoxia, insufficient nutrition, and glucose deficiency, the acetyl-CoA synthetase 2 (ACSS2)-mediated acetyl-CoA synthesis pathway plays an alternative role to ensure the normal operation of metabolic activities. To investigate the potential effect of the ACSS2 gene on hypoxic adaptation and its regulatory mechanism of gene expression in high-altitude cattle breeds, we analyzed the genetic variations of the ACSS2 gene in five Bos taurus taurus, Bos taurus indicus, hybrid Bos taurus taurus × Bos taurus indicus Chinese cattle breeds, and two Bos grunniens (yak) breeds distributed at different altitudes (95-3850 m). A total of 58 SNPs was detected in seven populations, and abundant genetic variation was found in high-altitude breeds. We identified the bovine ACSS2 core promoter region between g.-682 and g.-264 by using the luciferase assay in FFB and HepG2 cells. We also identified that the high-altitude hypoxia-specific haplotype (CAGTCT) was composed of six highly linked SNPs. The tagSNP g.-473 T>C (rs23) is located in the core promoter of ACSS2 in the Bos taurus taurus and yak breeds. The recombinant plasmid containing rs23 and analyses of luciferase activity of different genotypes showed that the activity of ACSS2 promoter increased significantly when T was mutated to C. We also found a yak-specific SNP rs20 that consists of 12 base insertions (g.-562 ins GAAAGGACCCTA) in the promoter of yak breeds. Luciferase activity analysis showed that the insertion mutant significantly decreased the promoter activity of ACSS2. Hence, ACSS2 may play an important role in the adaptation to high-altitude hypoxia by generating adaptive alleles to influence gene transcription in cattle. These results signify that different genetic variants and haplotypes affect the activity of the core promoter to regulate ACSS2 gene expression and subsequently overcome and adapt to a high-altitude environment within different cattle breeds. Our findings may have important implications for understanding the mechanism of adaptation to high altitude and for application of molecular breeding in Bos species.

In: Animal Biology

Abstract

Abiotic and biotic factors play an essential role in the structuring of natural communities. Aquatic ecosystems have complex interaction networks, encompassing predator/prey relationships and structural support. Among aquatic organisms, the order Odonata is a model group for understanding those relationships since they can be both predators and prey. Our hypotheses were that Zygoptera are (i) influenced positively by Ephemeroptera, Plecoptera and Trichoptera (EPT) and the Habitat Integrity Index (HII), and negatively by fish and macrophytes; and (ii) Anisoptera are affected positively by EPT and macrophytes, and negatively by fish and HII. We found that Zygoptera were affected by the fish functional trophic groups, while Anisoptera were affected by macrophytes, EPT, fish and HII. Macrophytes affected anisopterans positively because they provide perching sites for adults. The results for EPT and HII may be related since these organisms are also sensitive to environmental changes. More open areas have lower HII values and the negative relationship with Anisoptera may be explained by physiological constraints. The negative relationship between EPT and Anisoptera could be explained by the low occurrence of EPT in open sites, which are the sites that were highly rich in Anisoptera. Finally, the dominance of specific functional trophic groups of fish influences Odonata suborders in different ways. In conclusion, the results show the importance of ecological interactions for Odonata in Amazonian streams in both direct and indirect ways.

In: Animal Biology

Abstract

While larger groups tend to be better at making decisions, very few studies have explored how ecological variables, including predation pressure, shape how group size affects decision making. Our cross-population study of wild-caught guppies (Poecilia reticulata) shows that leading individuals from larger groups made faster decisions when deciding to leave the start area and reach the junction of a Y-maze, which allows for compromise over timing. However, at the junction of the Y when the fish needed to make a mutually exclusive decision that does not allow for compromise, there was no effect of group size in high predation fish on decision speed. In fish from low predation habitats, speed was fastest at the intermediate group size with a decline in speed in the largest group size. These results challenge the view that decision making always improves with group size and shows this effect depends on ecological and decision-making conditions.

In: Behaviour

Abstract

Here we describe the behaviour of a female blonde capuchin (Sapajus flavius) towards her dead infant and discuss possible explanations linked to the anecdotal event. We conducted our study in a fragment of Atlantic forest in Northeastern Brazil where we have been monitoring a blonde capuchin population, with over 163 individuals, since 2010. Our observations show that the behaviours of female blonde capuchins towards dead infant include corpse carrying, which may be related to maternal-bond strength and grief management. Two adult males cooperated with the vulnerable female by protecting her during group travelling even though offspring survival was no longer a possibility. The present study complements the current knowledge of thanatology in Neotropical primates.

In: Behaviour