Mammalian Biology

Finotti, Ricardo; Santori, Ricardo Tadeu; Almeida, Paulo José; Cerqueira, Rui

doi: 10.1016/j.mambio.2018.01.004pmid: N/A

Abstract We compared urine concentration capacity among three phylogenetically closed sigmodontine rodent species that occur in two distinct habitats: Necromys lasiurus (xeric), Akodon cursor and Akodon lindberghi (mesic). Water conservation ability was evaluated in 30 h-trials, with urine collected every 6 h. A control (I- water and food ad libitum) and a test (II- food and water deprivation) were conducted for each species. Body mass loss (BML), urine volume (UV), urine relative volume (UVr) and urine concentration (UC) were compared between experiments I and II for each species and among species. Changes in urine osmolality between experiments were modeled using exponential and sine functions. Circadian variation of urine concentration was obtained by sine functions fit to the experiments I. Best fit was achieved for sine functions with an accumulation term for experiments II, showing that even in stressful conditions the circadian variation is still present. Highest UC and lowest BML were obtained from Necromys lasiurus individuals, which achieved them at faster rates. The lowest UC with highest BML were obtained for A. cursor individuals at slower rates and values than A. lindberghi, which were intermediate. Necromys lasiurus is more adapted for xeric habitats achieving higher urine concentration in shorter time and faster rate than species of genus Akodon.

Loureiro, Livia O.; Lim, Burton K.; Engstrom, Mark D.

doi: 10.1016/j.mambio.2018.01.008pmid: N/A

Abstract We describe a new species of mastiff bat in the genus Molossus (Molossidae), which was previously confused with the common and widely distributed M. molossus, from Guyana and Ecuador based on morphological and molecular differences. It is diagnosed by the following set of morphological characteristics: bicolored dorsal pelage, rounded anterior arch of the atlas, triangular occipital bone, and smaller body and skull size. In a molecular phylogenetic analysis of mitochondrial and nuclear DNA, maximum likelihood and parsimony trees recovered eight clades in the genus and a polyphyletic relationship for the M. molossus species complex. The new species was recovered in a well-supported clade that can be genetically distinguished from other species in the genus by its high level of sequence divergence based on the mitochondrial CO1 gene (8.0-10.1%) and on the nuclear gene beta fibrinogen (1.0-3.1%). It is broadly sympatric with M. molossus sensu stricto in northern South America, but morphologically distinct and genetically divergent.

Kheswa, Enhle Z. Y.; Ramesh, Tharmalingam; Kalle, Riddhika; Downs, Colleen T.

doi: 10.1016/j.mambio.2018.01.009pmid: N/A

Abstract Land-use, the extent of cover, and intra-guild competition with larger predators all influence habitat use by mesocarnivores. Understanding this is especially important for little-known mesocarnivore species. We investigated the occurrence of the relatively understudied honey badger (Mellivora capensis) in iSimangaliso Wetland Park (St. Lucia, South Africa), a Protected Area that covers approximately 700 km2 with forestry plantations (agroforestry) on its Western Shores and restored natural vegetation on its Eastern Shores and Western Shores. We used single-season camera-trap data from a grid of 118 trap stations surveying continuously for 24 days, and estimated the probability of occupancy and detection of honey badgers, and modelled the influence of surrounding land-use, habitat characteristics and presence of other predators on each estimate. Mean estimated probability of occupancy of honey badgers was 0.38 ± 0.08 and probability of detection was 0.12 ± 0.03, with a naïve occupancy estimate of 0.25. Distance to water and higher number of trees in adjacent plantations influenced honey badger occupancy positively. Presence of leopard (Panthern pardus pardus) had a negative effect on detection probability of honey badger while presence of spotted hyena (Crocuta crocuta) positively influenced honey badger detection, indicating that the presence of individual predator species influenced honey badger habitat use in varying ways. We found a higher occurrence of honey badgers in Eucalyptus plantations than in natural habitat types. This suggests that human-modified landscapes may not always be detrimental to adaptable, or more habitat-generalised species that are able to exploit new habitat opportunities.

Brambilla, Alice; Brivio, Francesca

doi: 10.1016/j.mambio.2018.02.001pmid: N/A

Abstract Noisy human activities such as helicopter traffic may affect physiology and behaviour of wild animals. Since chronic behavioural modifications can ultimately alter reproductive success and population dynamics, studying the response of different taxa and species to human-induced disturbance in different habitats is paramount. The present study analysed data collected from 10 male Alpine ibex (Copra ibex) monitored with GPS collars to assess their response to disturbance caused by helicopter overflights. We compared ibex activity levels in the hours before and after 34 helicopter overflights during the summer of 2013 in Gran Paradiso National Park (Italy), a protected area that is essential for the conservation of Alpine ibex. The behaviour of Alpine ibex was affected both during and after helicopter overflights: compared to the average activity levels in the hours before the disturbance event, activity increased during the disturbance and decreased during the hour following the overflights. The reduction in activity persisted over the whole day of the helicopter disturbance and finally went back to normal levels during the following day. There was no evidence of habituation to the disturbance throughout the study period. The prolonged behavioural response to the disturbance suggests that frequent helicopter overflights may ultimately affect the ibex’s body conditions, as well as the life-history traits of a population. These findings highlight the importance of considering medium and long-term behavioural responses in assessing disturbance-related effects on wildlife populations.

de Bruina, Ruan; Ganswindt, André; Bennett, Nigel C.; Medger, Katarina

doi: 10.1016/j.mambio.2018.02.002pmid: N/A

Abstract Photoperiod and food availability often interact in the regulation of reproductive development in seasonal environments. We tested the effects of a 10% food restriction and short- (SD) and long-day (LD) photoperiods on reproductive preparedness of male spiny mice (Acomys spinosissimus) from South Africa. Males were either fed ad libitum or a 10% restricted diet and on both food regimes, they were exposed to either a 14h light:10h dark (LD) or 10h light:14h dark (SD) photoperiod. Testes size, seminiferous tubule diameter and faecal androgen metabolite (fAM) concentrations were larger in food restricted males subjected to LD than in any of the other groups. SD photoperiods did not suppress reproductive development, despite earlier findings, which may be explained by “spontaneous” recrudescence due to prolonged exposure to SD. The increased development of the gonads and higher fAM concentrations observed in food restricted LD males may indicate a terminal investment strategy in male spiny mice with males investing more into reproduction in the face of reduced future survival.

Hollerbach, Laura; Heurich, Marco; Reiners, Tobias Erik; Nowak, Carsten

doi: 10.1016/j.mambio.2018.02.003pmid: N/A

Abstract As Eurasian lynx (Lynx lynx) show signs of population recovery in parts of Central Europe, sound monitoring strategies are required to study population expansion, connectivity and genetic diversity. While non-invasive DNA sampling strategies could serve this task, genetic samples of lynx are generally hard to locate. To test the suitability of dog-based sampling we searched scat samples of lynx in the Bavarian Forest National Park, Germany, with two trained detection dog teams. In 44 grid cells of 2 × 2 km, dog teams covered 440 km of predetermined forest road and hiking trail transects during the four week survey. A total of 169 collected samples resulted in 52 genetically confirmed lynx detections, of which 26 were assigned to 11 individuals. Using a single-season site occupancy model we found a detection probability of 0.13/km (SD = 0.02), with 10 km of dog search per grid cell required to get a 70 % probability to detect lynx presence. Our results show that detection dogs are an appropriate tool for systematic genetic lynx monitoring. We argue that detection dog-assisted genetic monitoring may supplement monitoring strategies based on conventional camera trapping, especially when aiming to monitor genetic diversity and population connectivity.

Merlo, Julieta Leticia; Cutrera, Ana Paula; Kittlein, Marcelo Javier; Zenuto, Roxana Rita

doi: 10.1016/j.mambio.2018.02.007pmid: N/A

Abstract Several components of individual condition can modulate immune function in vertebrates. One of the most common techniques used by ecologists to estimate immune responsiveness in wild populations is the phytohemagglutinin (PHA)-skin test, which is usually considered a proxy of cell-mediated activity. To determine the influence of individual condition on the magnitude of this immune index we assessed the variability in the inflammatory response to PHA in the subterranean solitary rodent, Ctenomys talarum (Talas tuco-tucos), including 18 variables associated with different aspects of individual condition that are indicative of physical, physiological, parasitological and immunological state. A partial least square (PLS) regression analysis was performed on the condition and the response variables to identify those having greater contribution to overall variation in the response. The first two components explained together 77.5% of the maximum achievable explained variance in the inflammatory response to PHA (60% of total variance). Abundance of eggs of Trichuris pampeana, eosinophil, monocyte and neutrophil counts, together with reproductive condition were identified as the most important variables affecting the inflammatory response. The first component negatively associated the inflammatory response to PHA with the abundance of the nematode T. pampeana, and with counts of eosinophils and monocytes. The second component negatively associated the inflammatory response to PHA with reproductive condition, neutrophils and eosinophils. We discuss the general negative effect of infection on the immune responsiveness of wild animals and highlight the usefulness of the multivariate approaches in providing information on physiology, parasitology and health relationships to assess patterns of variation in immune responses.

Benedek, Ana Maria; Sîrbu, Ioan

doi: 10.1016/j.mambio.2018.02.008pmid: N/A

Abstract Intensification of agriculture is an increasing threat for biodiversity. Central Romania still preserves a traditional rural landscape with a matrix of small plots of crops and large surfaces covered by grasslands and forests, but its biodiversity is very poorly studied. Small mammals are key components of agrarian and semi-natural ecosystems but rodents are also viewed as major pests. Knowledge of the driving factors of small mammal communities in agricultural landscapes may enable taking management measures that pursue both conservation and economic goals. Here we evaluate the response of small mammals to environmental variables, including vegetation characteristics, land use and geographic position. We conducted live trapping between June and October in habitats with different environmental characteristics and land uses. We found that vegetation traits were the most important factors influencing small mammal communities. Species composition was shaped mainly by tree cover, shrub cover had strong effects on community diversity and abundance, while the height of the herbaceous layer significantly influenced all the parameters. Among the agrarian land uses maize crops stood out for the abundance of mice, especially Mus musculus, and hayfields for Microtus arvalis. Land fallowing was linked to the increase of diversity and total abundance to the maximum values but did not significantly alter species composition. Species with low tolerance to tree cover were more prone to be abundant in agricultural lands, whereas the habitat generalists prevailed in non-agrarian lands. Our results suggest that preservation of the mosaic of farmed and semi-natural habitats and actions targeted for vegetation management, such as interspersing woody vegetation in the crop matrix and mowing the herbaceous vegetation in semi-natural habitats adjacent to crops, may together achieve the balance between biodiversity conservation and crop protection.

de Medeiros Filho, Sérgio Almeida; de Carvalho-Neto, Francisco Geraldo; Garcia, Ana Cristina Lauer; Montes, Martín Alejandro; Duarte-Neto, Paulo José

doi: 10.1016/j.mambio.2018.03.002pmid: N/A

Abstract Rapid morphological changes associated with anthropogenic alterations have been reported in many groups of vertebrates. The Atlantic Forest is subject to serious conservation problems due to human activities and is one of the hotpots for the preservation of biodiversity. Bats play important roles in the recuperation of this type of environment as pollinators, seed dispersers and controllers of invertebrate populations. Environments altered by humans may serve as filters that determine the presence of animals with morphologically different characteristics in comparison to those found in preserved environments. In the present study, morphometric characteristics and weight were studied in flat-faced fruit-eating bats (Artibeus planirostris) captured in three protected areas of the Atlantic Forest located in the northern portion of the biome: one well preserved and two with conservation problems. The means of nearly all morphological characteristics evaluated were lower in the most conserved environment, including forearm size, which is directly related to flight and differed significantly between environments with different states of conservation. In recent decades, large and medium-sized trees have been cut down in the less conserved environments, resulting in fewer obstacles for bats during flight. This situation is thought to lead to selective pressure for bats with smaller wings in the more preserved environment, which implies greater flight manoeuvrability. The observation that the state of conservation of forest fragments affects morphometrics further underscores the importance of conservation measures in highly impacted biomes.

Carrión, Paola L.; Valle, Carlos A.

doi: 10.1016/j.mambio.2018.02.004pmid: N/A

Abstract Introduced cats (Felis catus) are one of the most serious threats to the native fauna of the Galapagos Islands, yet information about their impact on local species is still scarce. Studies from the 1980s indicate that the main prey items that make up the diets of introduced cats in the Galapagos include reptiles such as lava lizards and iguanas, land and marine birds, introduced mice and rats and several invertebrate species. In this study analyses of 132 cat fecal samples from San Cristobal Island confirmed the presence of mice, rats, invertebrates and lava lizards in the diet of feral cats; lava lizards being the most consumed prey. In the same analysis, we found a strong positive correlation between the number of cat feces and the number of lizards, mice and rats preyed upon by cats, which might indicate that cat feces could be used as an alternative tool to assess the level of cat predation in an area. Information on the dietary patterns of the introduced cats in the Galapagos might contribute to the development and improvement of conservation strategies to control or eradicate this invasive species on the islands and thus protect the endemic and emblematic species they prey on.