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1.
Sci Rep ; 13(1): 7388, 2023 05 06.
Article in English | MEDLINE | ID: mdl-37149712

ABSTRACT

Deciphering the origins of phenotypic variations in natural animal populations is a challenging topic for evolutionary and conservation biologists. Atypical morphologies in mammals are usually attributed to interspecific hybridisation or de-novo mutations. Here we report the case of four golden jackals (Canis aureus), that were observed during a camera-trapping wildlife survey in Northern Israel, displaying anomalous morphological traits, such as white patches, an upturned tail, and long thick fur which resemble features of domesticated mammals. Another individual was culled under permit and was genetically and morphologically examined. Paternal and nuclear genetic profiles, as well as geometric morphometric data, identified this individual as a golden jackal rather than a recent dog/wolf-jackal hybrid. Its maternal haplotype suggested past introgression of African wolf (Canis lupaster) mitochondrial DNA, as previously documented in other jackals from Israel. When viewed in the context of the jackal as an overabundant species in Israel, the rural nature of the surveyed area, the abundance of anthropogenic waste, and molecular and morphological findings, the possibility of an individual presenting incipient stages of domestication should also be considered.


Subject(s)
Canidae , Wolves , Dogs , Animals , Jackals/genetics , Wolves/genetics , Domestication , Biological Evolution
2.
Front Microbiol ; 14: 1080625, 2023.
Article in English | MEDLINE | ID: mdl-37206328

ABSTRACT

Soil microorganisms and free-living nematodes were investigated in association with the nesting and roosting habitats of the following piscivorous and omnivorous colonial birds: black kite (Milvus migrans), great cormorant (Phalacrocorax carbo), black-crowned night heron (Nycticorax nycticorax) and little egret (Egretta garzetta), in Israel's Mediterranean region. Abiotic variables, abundance, trophic structure, sex ratio and genus diversity of soil free-living nematodes, and total abundance of bacteria and fungi, were measured during the wet season, following our previous study conducted during the dry season. The observed soil properties were important drivers of soil biota structure. Presence of the most efficient elements for soil organisms, such as phosphorus and nitrogen, was strongly dependent on the diet of the compared piscivorous and omnivorous bird colonies; levels of these nutrients were notably higher in the bird habitats than in their respective control sites during the study period. Ecological indices showed that the different species of colonial birds can have different (stimulatory or inhibitory) impacts on abundance and diversity of the soil biota, affecting the structure of the soil free-living nematode population at the generic, trophic and sexual levels during the wet season. A comparison with results from the dry season illustrated that seasonal fluctuations can change, and even attenuate the effect of bird activity on the abundance, structure and diversity of the soil communities.

3.
Lancet Planet Health ; 7(4): e329-e335, 2023 04.
Article in English | MEDLINE | ID: mdl-37019573

ABSTRACT

The unprecedented economic and health impacts of the COVID-19 pandemic have shown the global necessity of mitigating the underlying drivers of zoonotic spillover events, which occur at the human-wildlife and domesticated animal interface. Spillover events are associated to varying degrees with high habitat fragmentation, biodiversity loss through land use change, high livestock densities, agricultural inputs, and wildlife hunting-all facets of food systems. As such, the structure and characteristics of food systems can be considered key determinants of modern pandemic risks. This means that emerging infectious diseases should be more explicitly addressed in the discourse of food systems to mitigate the likelihood and impacts of spillover events. Here, we adopt a scenario framework to highlight the many connections among food systems, zoonotic diseases, and sustainability. We identify two overarching dimensions: the extent of land use for food production and the agricultural practices employed that shape four archetypal food systems, each with a distinct risk profile with respect to zoonotic spillovers and differing dimensions of sustainability. Prophylactic measures to curb the emergence of zoonotic diseases are therefore closely linked to diets and food policies. Future research directions should explore more closely how they impact the risk of spillover events.


Subject(s)
COVID-19 , Communicable Diseases, Emerging , Animals , Humans , Pandemics , Zoonoses/epidemiology , Communicable Diseases, Emerging/epidemiology , Animals, Wild
4.
Animals (Basel) ; 12(5)2022 Mar 03.
Article in English | MEDLINE | ID: mdl-35268208

ABSTRACT

Populations at the warm edge of distribution are more genetically diverse, and at the same time are more susceptible to climate change. Between 1987-1996, we studied Tawny Owls in Israel, the species' global southern edge of distribution and a country undergoing a rapid land cover transformation for over a century. To assess the potential impacts of land cover transformation, we modelled the species' most suitable habitat and climate and analyzed how climate and habitat affected the nesting success and prey selection. Moreover, we monitored Tawny Owl juveniles' survival and ontogeny from eggs to dietary independent young, to find out whether the Israeli population is a sink. While the species distribution model correctly predicted the Tawny Owl's densest areas of occurrence, it failed to predict its occurrence in adjacent regions. The model also predicted that areas included in the species' historical range remained suitable habitats. The number of fledglings increased with precipitation and in rural settings but was adversely affected by extreme temperatures. While voles dominated the diet in all habitats, the Tawny Owl's diet is considerably more variable than other Israeli owls. Our results suggest that the Tawny Owl can adapt to rural-agricultural environments, but is susceptible to climate change.

5.
Sci Rep ; 11(1): 12877, 2021 06 18.
Article in English | MEDLINE | ID: mdl-34145353

ABSTRACT

Corrosion patterns induced by gastric fluids on the skeleton of prey animals may depend on the nature of the corrosive agents (acid, enzymes) as well as on the composition of the hard parts and the soft tissues that surround them. We propose a framework for predicting and interpreting corrosion patterns on lizard teeth, our model system, drawing on the different digestive pathways of avian and non-avian vertebrate predators. We propose that high-acid, low-enzyme systems (embodied by mammalian carnivores) will lead to corrosion of the tooth crowns, whereas low-acid, high-enzyme systems (embodied by owls) will lead to corrosion of the tooth shafts. We test our model experimentally using artificial gastric fluids (with HCl and pepsin) and feeding experiments, and phenomenologically using wild-collected owl pellets with lizard remains. Finding an association between the predictions and the experimental results, we then examine corrosion patterns on nearly 900 fossil lizard jaws. Given an appropriate phylogenetic background, our focus on physiological rather than taxonomic classes of predators allows the extension of the approach into Deep Time.


Subject(s)
Dental Caries/pathology , Fossils , Lizards , Tooth/pathology , Animal Feed , Animals , Digestion , Disease Models, Animal , Ferrets , Paleontology , Tooth/anatomy & histology
6.
J Hum Evol ; 160: 102652, 2021 11.
Article in English | MEDLINE | ID: mdl-31623862

ABSTRACT

This paper describes the micromammalian remains and paleoenvironment of the Upper Paleolithic sequence of Manot Cave (46-34 ka), southern Levant. Micromammal remains were identified from Ahmarian (46-42 ka), Levantine Aurignacian (38-34 ka) and post-Levantine Aurignacian (34-33 ka) layers. To identify taphonomic agents, molar digestion was modelled for seven local raptor species, and model predictions were compared with observed digestion scores in the Manot Cave material. Raptor species differed significantly in molar digestion patterns, allowing us to identify Tyto alba as the bone accumulator in the Ahmarian and Post-Levantine Aurignacian units. Data were insufficient for species-level identification of the taphonomic agent in the Levantine Aurignacian. Günther's voles (Microtus guentheri) were dominant, though woodland species (Apodemus spp., Sciurus anomalus and Dryomys nitedula) also occurred through the entire sequence. Manot Cave furnished the first fossil record of the Eurasian snow vole (Chionomys nivalis) in the southern Levant during the Late Pleistocene and its first secure record of the water vole (Arvicola terrestris) outside the Hula Valley. Records of other taxa (Acomys dimidiatus and D. nitedula) provide the earliest occurrence datum in the region. Using counts of both identified specimens and distinct elements (lower first molars) we modelled paleoenvironmental conditions through both Weighted Averaging Partial Least Squares regression and a qualitative analysis considering niche preferences of species. Model predictions indicate the unexpectedly pronounced dominance of open habitats compared to present conditions near the cave, though the occurrence and abundance of woodland species also indicate some woodland expansion relative to the preceding Middle Paleolithic period. Combining statistical models and species niche considerations we show that the time span between the Ahmarian, Levantine Aurignacian and post-Levantine Aurignacian was marked by a clear-cut climatic oscillation to cooler and likely wetter conditions.


Subject(s)
Archaeology , Caves , Ecosystem , Fossils , Israel
7.
BMC Ecol ; 19(1): 52, 2019 12 17.
Article in English | MEDLINE | ID: mdl-31847851

ABSTRACT

BACKGROUND: In recent decades, a decrease of passerine densities was documented in Mediterranean shrublands. At the same time, a widespread encroachment of Aleppo pines (Pinus halepensis) to Mediterranean shrubland occurred. Such changes in vegetation structure may affect passerine predator assemblage and densities, and in turn impact passerine densities. Depredation during the nesting season is an important factor to influence passerine population size. Understanding the effects of changes in vegetation structure (pine encroachment) on passerine nesting success is the main objective of this study. We do so by assessing the effects of Aleppo pine encroachment on Sardinian warbler (Sylvia melanocephala) nest depredation in Mediterranean shrublands. We examined direct and indirect predation pressures through a gradients of pine density, using four methods: (1) placing dummy nests; (2) acoustic monitoring of mobbing events; (3) direct observations on nest predation using cameras; and (4) observation of Eurasian jay (Garrulus glandarius) behaviour as indirect evidence of predation risk. RESULTS: We found that Aleppo pine encroachment to Mediterranean shrublands increased nest predation by Eurasian jays. Nest predation was highest in mixed shrubland and pines. These areas are suitable for warblers but had high occurrence rate of Eurasian jays. CONCLUSIONS: Encroaching pines directly increase activity of Eurasian jays in shrubland habitats, which reduced the nesting success of Sardinian warblers. These findings are supported by multiple methodologies, illustrating different predation pressures along a gradient of pine densities in natural shrublands. Management of Aleppo pine seedlings and removal of unwanted trees in natural shrubland might mitigate arrival and expansion of predators and decrease the predation pressure on passerine nests.


Subject(s)
Passeriformes , Pinus , Songbirds , Animals , Nesting Behavior , Predatory Behavior
8.
PLoS One ; 13(6): e0198747, 2018.
Article in English | MEDLINE | ID: mdl-29912923

ABSTRACT

Analysis of ca. 17,000 fish remains recovered from the late Upper Paleolithic/early Epi-Paleolithic (LGM; 23,000 BP) waterlogged site of Ohalo II (Rift Valley, Israel) provides new insights into the role of wetland habitats and the fish inhabiting them during the evolution of economic strategies prior to the agricultural evolution. Of the current 19 native fish species in Lake Kinneret (Sea of Galilee), eight species were identified at Ohalo II, belonging to two freshwater families: Cyprinidae (carps) and Cichlidae (St. Peter fish). Employing a large set of quantitative and qualitative criteria (NISP, species richness, diversity, skeletal element representation, fragmentation, color, spatial distribution, etc.), we demonstrate that the inhabitants of Ohalo II used their knowledge of the breeding behavior of different species of fish, for year-round intensive exploitation.


Subject(s)
Fisheries/history , Fossils , Animals , Fisheries/economics , Fishes , History, Ancient , Humans , Lakes , Middle East
9.
Ecol Evol ; 8(6): 3382-3392, 2018 03.
Article in English | MEDLINE | ID: mdl-29607033

ABSTRACT

Ecological theory suggests that prey size should increase with predator size, but this trend may be masked by other factors affecting prey selection, such as environmental constraints or specific prey preferences of predator species. Owls are an ideal case study for exploring how predator body size affects prey selection in the presence of other factors due to the ease of analyzing their diets from owl pellets and their widespread distributions, allowing interspecific comparisons between variable habitats. Here, we analyze various dimensions of prey resource selection among owls, including prey size, taxonomy (i.e., whether or not particular taxa are favored regardless of their size), and prey traits (movement type, social structure, activity pattern, and diet). We collected pellets of five sympatric owl species (Athene noctua, Tyto alba, Asio otus, Strix aluco, and Bubo bubo) from 78 sites across the Mediterranean Levant. Prey intake was compared between sites, with various environmental variables and owl species as predictors of abundance. Despite significant environmental impacts on prey intake, some key patterns emerge among owl species studied. Owls select prey by predator body size: Larger owls tend to feed on wider ranges of prey sizes, leading to higher means. In addition, guild members show both specialization and generalism in terms of prey taxa, sometimes in contrast with the expectations of the predator-prey body size hypothesis. Our results suggest that while predator body size is an important factor in prey selection, taxon specialization by predator species also has considerable impact.

10.
Zoology (Jena) ; 128: 62-68, 2018 06.
Article in English | MEDLINE | ID: mdl-29699824

ABSTRACT

Many factors affect individual fitness, but while some factors, such as resource availability, have received strong experimental support, others including interspecific competition have rarely been quantified. Nevertheless, interspecific competition is commonly mentioned in the context of reproductive success and fitness. In general, when reproduction is likely to fail, reproductive suppression may occur. We studied the golden spiny mouse (Acomys russatus) and the common spiny mouse (A. cahirinus; however, recent molecular analysis in spiny mice from Jordan and Sinai suggests this species is A. dimidiatus (Frynta et al., 2010), as a model for the effect of competition on reproduction in four field enclosures: two populated only by A. russatus individuals, and two populated by individuals of both species. In presence of A. cahirinus, fitness of A. russatus was lower: the number of A. rusatus offspring was significantly lower; more males had regressed testes (indicating reproductive depression); more A. russatus young had damaged tails. However, no clear effect was evident in A. russatus female vaginal smear cytology. We conclude that the presence of A. cahirinus impairs fitness and reproductive success of A. russatus. While various direct and/or indirect mechanisms may be responsible for the effect of competition on reproduction, a plausible mechanism is increased use of torpor induced by the presence of A. cahirinus previously documented in A. russatus.


Subject(s)
Muridae/physiology , Animals , Desert Climate , Female , Male , Mice , Reproduction/physiology , Species Specificity
11.
Nat Ecol Evol ; 1(12): 1889-1895, 2017 Dec.
Article in English | MEDLINE | ID: mdl-29109469

ABSTRACT

Most modern mammals, including strictly diurnal species, exhibit sensory adaptations to nocturnal activity that are thought to be the result of a prolonged nocturnal phase or 'bottleneck' during early mammalian evolution. Nocturnality may have allowed mammals to avoid antagonistic interactions with diurnal dinosaurs during the Mesozoic. However, understanding the evolution of mammalian activity patterns is hindered by scant and ambiguous fossil evidence. While ancestral reconstructions of behavioural traits from extant species have the potential to elucidate these patterns, existing studies have been limited in taxonomic scope. Here, we use an extensive behavioural dataset for 2,415 species from all extant orders to reconstruct ancestral activity patterns across Mammalia. We find strong support for the nocturnal origin of mammals and the Cenozoic appearance of diurnality, although cathemerality (mixed diel periodicity) may have appeared in the late Cretaceous. Simian primates are among the earliest mammals to exhibit strict diurnal activity, some 52-33 million years ago. Our study is consistent with the hypothesis that temporal partitioning between early mammals and dinosaurs during the Mesozoic led to a mammalian nocturnal bottleneck, but also demonstrates the need for improved phylogenetic estimates for Mammalia.


Subject(s)
Biological Evolution , Circadian Rhythm , Dinosaurs , Mammals/physiology , Animals , Fossils , Phylogeny
12.
J Environ Manage ; 202(Pt 1): 276-286, 2017 Nov 01.
Article in English | MEDLINE | ID: mdl-28738201

ABSTRACT

Global demand for freshwater is increasing as human population grows, climate changes and water resources are being overexploited. Consequently, many freshwater ecosystems, particularly in water-stressed regions, are severely degraded. Here we present a unique case of an Interbasin Water Transfer (IWT) project aiming at ecosystem rehabilitation and recreation enhancement of an intermittent transboundary stream (Ayun, Israel). For the past century, water diversion at the Lebanese side had led to flow secession in the Israeli Ayun Nature Reserve during the dry season (May-November). To restore flow continuum, a sum of 0.5 million cubic meters of high quality freshwaters have been allocated annually during the dry months. The aim of this study is to evaluate the IWT project by: (1) examining the correlation between water flow in the Ayun and recreational visitation, and (2) performing a cost-benefit analysis of the IWT scheme, including non-market benefits. A time-series regression (Adj. R2 = 0.688, n = 125) shows that a 10% increase in water flow corresponds to a 2.1% increase in monthly visitors. An estimated 18.8% of the visitation rate between 2009 and 2015 can be attributed to the water reallocation project. Through a single-site travel cost model, we estimate the visitor's willingness to pay in US$ 37.8 per person per trip. When non-market benefits for recreation are included, the total benefits of the IWT project substantially exceed its costs. Our results suggest that IWT can be applied to restore water flow and enhance ecosystem services also in water-stressed regions.


Subject(s)
Conservation of Natural Resources , Ecosystem , Recreation , Humans , Israel , Rivers , Water
13.
Am Nat ; 188(2): 205-18, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27420785

ABSTRACT

Although animals fine-tune their activity to avoid excess heat, we still lack a mechanistic understanding of such behaviors. As the global climate changes, such understanding is particularly important for projecting shifts in the activity patterns of populations and communities. We studied how foraging decisions vary with biotic and abiotic pressures. By tracking the foraging behavior of diurnal desert spiny mice in their natural habitat and estimating the energy and water costs and benefits of foraging, we asked how risk management and thermoregulatory requirements affect foraging decisions. We found that water requirements had the strongest effect on the observed foraging decisions. In their arid environment, mice often lose water while foraging for seeds and cease foraging even at high energetic returns when water loss is high. Mice also foraged more often when energy expenditure was high and for longer times under high seed densities and low predation risks. Gaining insight into both energy and water balance will be crucial to understanding the forces exerted by changing climatic conditions on animal energetics, behavior, and ecology.


Subject(s)
Appetitive Behavior/physiology , Murinae/physiology , Water Loss, Insensible/physiology , Animals , Body Temperature/physiology , Desert Climate , Ecosystem , Israel , Predatory Behavior , Seeds
14.
PLoS One ; 11(7): e0156964, 2016.
Article in English | MEDLINE | ID: mdl-27383247

ABSTRACT

The current view for the southern Levant is that wild game hunting was replaced by herd management over the course of the Pre-Pottery Neolithic B period, but there is significant debate over the timing, scale and origin of this transition. To date, most relevant studies focus either on wild game exploitation in the periods prior to domestication or on classic markers of domestication of domestic progenitor species over the course of the PPNB. We studied the faunal remains from the 2007-2008 excavations of the Middle PPNB (MPPNB) site of Yiftah'el, Northern Israel. Our analysis included a close examination of the timing and impact of the trade-off between wild game and domestic progenitor taxa that reflects the very beginning of this critical transition in the Mediterranean zone of the southern Levant. Our results reveal a direct trade-off between the intensive hunting of wild ungulates that had been staples for millennia, and domestic progenitor taxa. We suggest that the changes in wild animal use are linked to a region-wide shift in the relationship between humans and domestic progenitor species including goat, pig and cattle.


Subject(s)
Animal Husbandry/history , Archaeology , Human Activities/history , Animals , Animals, Wild , Cattle , Female , Geography , Goats , History, Ancient , Humans , Israel , Male , Swine
15.
PLoS One ; 11(1): e0145978, 2016.
Article in English | MEDLINE | ID: mdl-26815653

ABSTRACT

Several projects aimed at identifying priority issues for conservation with high relevance to policy have recently been completed in several countries. Two major types of projects have been undertaken, aimed at identifying (i) policy-relevant questions most imperative to conservation and (ii) horizon scanning topics, defined as emerging issues that are expected to have substantial implications for biodiversity conservation and policy in the future. Here, we provide the first overview of the outcomes of biodiversity and conservation-oriented projects recently completed around the world using this framework. We also include the results of the first questions and horizon scanning project completed for a Mediterranean country. Overall, the outcomes of the different projects undertaken (at the global scale, in the UK, US, Canada, Switzerland and in Israel) were strongly correlated in terms of the proportion of questions and/or horizon scanning topics selected when comparing different topic areas. However, some major differences were found across regions. There was large variation among regions in the percentage of proactive (i.e. action and response oriented) versus descriptive (non-response oriented) priority questions and in the emphasis given to socio-political issues. Substantial differences were also found when comparing outcomes of priority questions versus horizon scanning projects undertaken for the same region. For example, issues related to climate change, human demography and marine ecosystems received higher priority as horizon scanning topics, while ecosystem services were more emphasized as current priority questions. We suggest that future initiatives aimed at identifying priority conservation questions and horizon scanning topics should allow simultaneous identification of both current and future priority issues, as presented here for the first time. We propose that further emphasis on social-political issues should be explicitly integrated into future related projects.


Subject(s)
Conservation of Natural Resources , Biodiversity , Canada , Climate Change , Demography , Ecosystem , Humans , Israel , Policy , Switzerland
16.
Proc Biol Sci ; 280(1765): 20123088, 2013 Aug 22.
Article in English | MEDLINE | ID: mdl-23825199

ABSTRACT

Most studies in chronobiology focus on solar cycles (daily and annual). Moonlight and the lunar cycle received considerably less attention by chronobiologists. An exception are rhythms in intertidal species. Terrestrial ecologists long ago acknowledged the effects of moonlight on predation success, and consequently on predation risk, foraging behaviour and habitat use, while marine biologists have focused more on the behaviour and mainly on reproduction synchronization with relation to the Moon phase. Lately, several studies in different animal taxa addressed the role of moonlight in determining activity and studied the underlying mechanisms. In this paper, we review the ecological and behavioural evidence showing the effect of moonlight on activity, discuss the adaptive value of these changes, and describe possible mechanisms underlying this effect. We will also refer to other sources of night-time light ('light pollution') and highlight open questions that demand further studies.


Subject(s)
Feeding Behavior/physiology , Invertebrates/physiology , Light , Moon , Animals , Behavior, Animal/physiology , Circadian Rhythm/physiology , Predatory Behavior/physiology , Reproduction/physiology , Vertebrates/physiology
17.
Ecol Lett ; 15(11): 1240-1248, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22906198

ABSTRACT

We studied the relationship between sequence of foraging, energy acquired and use of torpor as an energy-balancing strategy in diurnally active desert golden spiny mice. We hypothesised that individuals that arrive earlier to forage will get higher returns and consequently spend less time torpid. If that is the case, then early foragers can be viewed as more successful; if the same individuals arrive repeatedly early, they are likely to have higher fitness under conditions of resource limitation. For the first time, we show a relationship between foraging sequence and amount of resources removed, with individuals that arrive later to a foraging patch tending to receive lower energetic returns and to spend more time torpid. Torpor bears not only benefits but also significant costs, so these individuals pay a price both in lower energy intake and in extended periods of torpor, in what may well be a positive feedback loop.


Subject(s)
Adaptation, Physiological , Energy Metabolism , Feeding Behavior , Murinae/physiology , Animals , Circadian Rhythm , Population Dynamics , Temperature
18.
Am Nat ; 179(6): 794-804, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22617266

ABSTRACT

Most mammals can be characterized as nocturnal or diurnal. However infrequently, species may overcome evolutionary constraints and alter their activity patterns. We modeled the fundamental temporal niche of a diurnal desert rodent, the golden spiny mouse, Acomys russatus. This species can shift into nocturnal activity in the absence of its congener, the common spiny mouse, Acomys cahirinus, suggesting that it was competitively driven into diurnality and that this shift in a small desert rodent may involve physiological costs. Therefore, we compared metabolic costs of diurnal versus nocturnal activity using a biophysical model to evaluate the preferred temporal niche of this species. The model predicted that energy expenditure during foraging is almost always lower during the day except during midday in summer at the less sheltered microhabitat. We also found that a shift in summer to foraging in less sheltered microhabitats in response to predation pressure and food availability involves a significant physiological cost moderated by midday reduction in activity. Thus, adaptation to diurnality may reflect the "ghost of competition past"; climate-driven diurnality is an alternative but less likely hypothesis. While climate is considered to play a major role in the physiology and evolution of mammals, this is the first study to model its potential to affect the evolution of activity patterns of mammals.


Subject(s)
Biological Evolution , Circadian Rhythm , Feeding Behavior , Models, Biological , Murinae/physiology , Adaptation, Physiological , Animals , Body Temperature , Ecosystem , Energy Metabolism , Temperature , Water/metabolism
19.
PLoS One ; 6(8): e23446, 2011.
Article in English | MEDLINE | ID: mdl-21829733

ABSTRACT

We studied stress hormones and foraging of nocturnal Acomys cahirinus and diurnal A. russatus in field populations as well as in two field enclosures populated by both species and two field enclosures with individuals of A. russatus alone. When alone, A. russatus individuals become also nocturnally active. We asked whether nocturnally active A. russatus will respond to moon phase and whether this response will be obtained also in diurnally active individuals. We studied giving-up densities (GUDs) in artificial foraging patches and fecal cortisol metabolite levels. Both species exhibited elevated fecal cortisol metabolite levels and foraged to higher GUDs in full moon nights; thus A. russatus retains physiological response and behavioral patterns that correlate with full moon conditions, as can be expected in nocturnal rodents, in spite of its diurnal activity. The endocrinological and behavioral response of this diurnal species to moon phase reflects its evolutionary heritage.


Subject(s)
Feces , Feeding Behavior , Hydrocortisone/metabolism , Moon , Animals , Circadian Rhythm , Mice
20.
Integr Comp Biol ; 51(3): 441-8, 2011 Sep.
Article in English | MEDLINE | ID: mdl-21719432

ABSTRACT

We studied the occurrence of torpor in golden spiny mice in a hot rocky desert near the Dead Sea. In this rodent assemblage, a congener, the nocturnal common spiny mouse, competitively excluded the golden spiny mouse from the nocturnal part of the diel cycle and forced it into diurnal activity; this temporal partitioning allows the two species to partition their prey populations, particularly in summer when the diet of the two species is comprised mainly of arthropods, and largely overlap. We studied the effect of the presence of the common spiny mice at two resource levels (natural food availability and food added ad libitum) on populations of golden spiny mice in four large outdoor enclosures: two with common spiny mice removed and two enclosures with populations of both species. We hypothesized that with interspecific competition and/or reduced resources, golden spiny mice will increase their use of torpor. As we expected, supplemented food reduced the total time spent torpid. In summer, when the different activity periods of the two species results in prey species partitioning, removal of the congener did not affect torpor in the golden spiny mouse. However, in winter, when insect populations are low and the two species of mice overlap in a largely vegetarian diet, removal of the common spiny mouse reduced torpor in golden spiny mice, whether food was supplemented or not. This result suggests that torpor, a mechanism that allows small mammals to sustain periods of low availability of resources or high energetic requirements, may also help them to tolerate periods of enhanced interspecific competition. This may be a significant short-term mechanism that reduces competition and hence increases fitness, in particular of individuals of the subordinate species whose accessibility to resources may be limited.


Subject(s)
Body Temperature Regulation , Competitive Behavior , Feeding Behavior , Murinae/physiology , Animals , Circadian Rhythm , Desert Climate , Female , Israel , Male , Motor Activity , Seasons , Sympatry
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