Bornholdt, R., Helgen, K., Koepfli, K.-P., Oliveira, L., Lucherini, M. and Eizirik, E. (2013), Taxonomic revision of the genus Galictis (Carnivora: Mustelidae): species delimitation, morphological diagnosis, and refined mapping of geographical distribution. Zoological Journal of the Linnean Society, 167: 449–472. doi: 10.1111/j.1096-3642.2012.00859.x
Although critical for enabling in-depth evolutionary, ecological, or conservation-orientated studies, taxonomic knowledge is still scarce for many groups of organisms, including mammals of the order Carnivora. For some of these taxa, even basic aspects such as species limits and geographical distribution are still uncertain. This is the case for the Neotropical mustelid genus Galictis, considered one of the least studied carnivoran genera in the Americas. To address this issue, we performed a comprehensive assessment of morphological and molecular characters to test the number of species within Galictis, and to characterize their distinctiveness and evolutionary history. In addition, we reviewed and consolidated the available information on the taxonomy of this genus, so as to provide a historical framework upon which we could interpret our data. Our analyses demonstrated that two Galictis species can be clearly delimited and diagnosed using metric and nonmetric morphological characters as well as DNA sequences from mitochondrial and nuclear gene segments. On the basis of this clarified species-level delimitation, we reassessed the geographical range of each Galictis taxon, identifying possible areas of sympatry between them. These results provide a solid taxonomic framework for Galictis, enabling the development of additional studies focusing on this poorly known taxon.
Gobekko cretacicus (Reptilia: Squamata) and its bearing on the interpretation of gekkotan affinities
Juan D. Daza, Aaron M. Bauer, Eric Snively
Zoological Journal of the Linnean Society, 2013, 167, 430–448.
Gobekko cretacicus, a Cretaceous lizard from the Gobi Desert of Mongolia, is a key fossil for understanding gecko phylogeny. We revisit this fossil using high-resolution X-ray computed tomography. The application of this imaging method reveals new information about sutures, bone shape, and structural details of the palate and basicranium. These data were used to assess the phylogenetic affinities of Gobekko in the context of an existing squamate data set. The effects of character ordering, search strategy, and the addition of another putative gekkonomorph (Hoburogekko suchanovi) on inferred gekkonomorph relationships were explored. Available specimens of G. cretacicus are skeletally mature but have unfused nasals, frontals, and parietals, and (possibly) a persistent basicranial fenestra. Some putative gekkonomorphs are not consistently supported as closer to crown clade gekkotans than to autarchoglossans. In a strict consensus both Gobekko and Hoburogekko form a polytomy with extant geckos. Some of the adult character states of Gobekko are observable in embryos of extant species. The evolution of tubular frontals and dentaries in gekkotans may be structurally related to the loss of the postorbital and supratemporal bars in this lineage. The complete lack of a parietal foramen, and presumably a light-sensitive parietal eye, in this clade is of interest and could indicate an early origin of nocturnality in geckos.
CHARPENTIER, M. J.E., MBOUMBA, S., DITSOGA, C. and DREA, C. M. (2013), Nasopalatine Ducts and Flehmen Behavior in the Mandrill: Reevaluating Olfactory Communication in Old World Primates. Am. J. Primatol.. doi: 10.1002/ajp.22146
Compared to other modes of communication, chemical signaling between conspecifics generally has been overlooked in Old World primates, despite the presence in this group of secretory glands and scent-marking behavior, as well as the confirmed production and perception of olfactory signals. In other mammalian species, flehmen is a behavior thought to transport primarily nonvolatile, aqueous-soluble odorants via specialized ducts to the vomeronasal organ (VNO). By contrast, Old World primates are traditionally thought to lack a functional VNO, relying instead on the main olfactory system to process volatile odorants from their environment. Here, in the mandrill (Mandrillus sphinx), we document unusual morphological and behavioral traits that typically are associated with the uptake of conspecific chemical cues for processing by an accessory olfactory system. Notably, we confirmed that both sexes possess open nasopalatine ducts and, in response to the presentation of conspecific odorants, we found that both sexes showed stereotyped behavior consistent with the flehmen response. If, as in other species, flehmen in the mandrill serves to mediate social or reproductive information, we expected its occurrence to vary with characteristics of either the signaler or receiver. Flehmen, particularly in a given male, occurred most often in response to odorants derived from male, as opposed to female, conspecifics. Moreover, odorants derived during the breeding season elicited more flehmen responses than did odorants collected during the birthing season. Lastly, odorants from reproductively cycling females also elicited more responses than did odorants from contracepted females. Although confirming a link between the nasopalatine ducts, flehmen behavior, and olfactory processing in mandrills would require further study, our observations provide new information to suggest anatomical variability within Old World primates, calling further attention to the underappreciated role of chemical communication in this lineage.
EHLERS SMITH, D. A. and EHLERS SMITH, Y. C. (2013), Population Density of Red Langurs in Sabangau Tropical Peat-Swamp Forest, Central Kalimantan, Indonesia. Am. J. Primatol.. doi: 10.1002/ajp.22145
Because of the large-scale destruction of Borneo’s rainforests on mineral soils, tropical peat-swamp forests (TPSFs) are increasingly essential for conserving remnant biodiversity, particularly in the lowlands where the majority of habitat conversion has occurred. Consequently, effective strategies for biodiversity conservation are required, which rely on accurate population density and distribution estimates as a baseline. We sought to establish the first population density estimates of the endemic red langur (Presbytis rubicunda) in Sabangau TPSF, the largest remaining contiguous lowland forest-block on Borneo. Using Distance sampling principles, we conducted line transect surveys in two of Sabangau’s three principle habitat sub-classes and calculated group density at 2.52 groups km−2 (95% CI 1.56–4.08) in the mixed-swamp forest sub-class. Based on an average recorded group size of 6.95 individuals, population density was 17.51 ind km−2, the second highest density recorded in this species. The accessible area of the tall-interior forest, however, was too disturbed to yield density estimates representative of the entire sub-class, and P. rubicunda was absent from the low-pole forest, likely as a result of the low availability of the species‘ preferred foods. This absence in 30% of Sabangau’s total area indicates the importance of in situ population surveys at the habitat-specific level for accurately informing conservation strategies. We highlight the conservation value of TPSFs for P. rubicunda given the high population density and large areas remaining, and recommend 1) quantifying the response of P. rubicunda to the logging and burning of its habitats; 2) surveying degraded TPSFs for viable populations, and 3) effectively delineating TPSF sub-class boundaries from remote imagery to facilitate population estimates across the wider peat landscape, given the stark contrast in densities found across the habitat sub-classes of Sabangau.
TIAN, J.-D., WANG, Z.-L., LU, J.-Q., WANG, B.-S. and CHEN, J.-R. (2013), Reproductive Parameters of Female Macaca mulatta tcheliensis in the Temperate Forest of Mount Taihangshan, Jiyuan, China. Am. J. Primatol.. doi: 10.1002/ajp.22147
The remaining population of Macaca mulatta tcheliensis, approximately 3,000 individuals, is currently confined to the southern region of Mount Taihangshan, northern China. Using data collected from February 2003 to November 2012, we examined female reproductive characteristics in a seasonally food supplemented free-ranging group of M. m. tcheliensis (Wangwu 1, WW-1), inhabiting the Taishangshan Macaque National Nature Reserve (TMNNR), Jiyuan, China. We tested a series of predictions regarding the degree to which M. m. tcheliensis is best considered as a “strict income breeder,” a “relaxed income breeder” or a “capital breeder.” This group was comprised 18 adult females who produced 64 infants over the 10-year study period. In our study group (WW-1) adult female macaques gave birth to an average of 0.71 ± 0.26 infants per year. Infant mortality was 13.4 ± 19.3%. The age at first birth for mothers was 4.9 ± 0.5 years old. The mean inter-birth interval (IBI) was 15.4 ± 4.9 months. Based on the fact M. m. tcheliensis is a strictly seasonal breeder (76.6% of births occurred between April and May) with infants born during a time of the year when food availability appears to be high, and that their IBI is intermediate in length compared with other macaque populations, our results suggest that M. m. tcheliensis follows a birth pattern most consistent with a “relaxed income breeder” strategy.
Stefanie Neuhauser, Svenja Rheinfeld, Johannes Handler, Motility of Fresh and Frozen-Thawed Stallion Sperm from Three Segments of the Epididymal Cauda and the Effect of Post-Thaw Seminal Plasma Addition on Motility, Journal of Equine Veterinary Science, Available online 23 March 2013, ISSN 0737-0806, 10.1016/j.jevs.2013.02.001.
Preservation of epididymal spermatozoa is an advantageous method to preserve genetic material of endangered species or valuable breeding animals after sudden death and injuries. Despite lower pregnancy rates, fertilization with epididymal sperm has been proven successful. Variable sperm quality after cryopreservation among individual stallions and the usually terminal chance to preserve epididymal sperm are opportunities for the development of a freezing procedure suitable for the majority of stallions. To evaluate the effect of the preservation procedure, we analyzed the sperm motion characteristics after every step of processing. In addition, we investigated the influence of seminal plasma on motility of frozen-thawed semen. We compared three segments of the cauda epididymidis and harvested spermatozoa by retrograde flushing (most caudal part) and mincing (more cranial segments) to augment the number of spermatozoa. During processing, there were differences in sperm motion characteristics depending on the segment of the cauda epididymidis. Distinct increases in motility due to different extenders and the effect of seminal plasma suggest that motion characteristics of raw and frozen-thawed spermatozoa are strongly influenced by microenvironment and must be interpreted with caution.
Carlos Eduardo Camargo, Romildo Romualdo Weiss, Luiz Ernandes Kozicki, Marilia Pastorello Duarte, Mario Cesar Garcia Duarte, Diego Lunelli, Saulo Weber, Renata Azevedo de Abreu, Some Factors Affecting the Rate of Pregnancy after Embryo Transfer Derived from the Brazilian Jumper Horse Breed, Journal of Equine Veterinary Science, Available online 23 March 2013, ISSN 0737-0806, 10.1016/j.jevs.2013.01.008.
This study aimed to evaluate the effects of certain embryo transfer parameters on the pregnancy rate after equine embryo transfer of the Brazilian Jumper Horse breed. The size, embryonic development stage, embryo quality, and synchronization of ovulation between the donor (n = 120) and recipient (n = 420) were evaluated in 396 embryos. Embryo recovery was performed on Day 6-9 after ovulation (Day 0 = day of ovulation). The recipient mares were chosen on the day of embryo recovery, and the transfers were performed that same day. The embryo size (diameter including envelopes; n = 396) ranged from 150 to 3000 μm; 67.1% measured between 400 and 1199 μm. The embryo size (400-1199 μm vs. ≤399 μm); stage of development (n = 396; blastocyst and expanded blastocyst versus compact morula and early blastocyst); quality (n = 396; grade 1 [excellent]), 2 [good], or 3 [poor]); and synchronization of ovulation between the donor and recipient (0, 1, 2, 3, and 4 days versus −1, 5, and 6 days, respectively) all affected pregnancy rate (P < .05). The pregnancy rate did not differ significantly among transfers performed on Days 0, 1, 2, 3, and 4. In conclusion, embryos measuring 400-1199 μm produced higher pregnancy rates in recipients than embryos measuring 150-399 μm, and blastocysts and expanded blastocysts produced pregnancy more efficiently than morulae and early blastocysts. The embryo quality also affected the pregnancy rate. Synchronization of donor and recipient ovulation to Days 0-4 improved the efficiency of embryo transplant.
Joan B. Silk, Sarah F. Brosnan, Joseph Henrich, Susan P. Lambeth, Steven Shapiro, Chimpanzees share food for many reasons: the role of kinship, reciprocity, social bonds and harassment on food transfers, Animal Behaviour, Available online 23 March 2013, ISSN 0003-3472, 10.1016/j.anbehav.2013.02.014.
There is currently great interest in the phylogenetic origins of altruistic behaviour within the primate order. Considerable attention has been focused on chimpanzees, Pan troglodytes, because they are our closest living relatives and participate in a wide range of collective activities, including hunting and food sharing. Food sharing is of particular importance because it plays a critical role in the human foraging niche, but food sharing among adults is rare in nonhuman primates. Some research suggests that chimpanzees selectively share meat with reciprocating partners and allies, while other work indicates that chimpanzees primarily share to reduce harassment from other group members (tolerated theft). We examined the effects of kinship, relationship quality, reciprocity and the intensity of solicitations on the pattern of food transfers in six captive groups of chimpanzees. We observed events that occurred after the chimpanzees were provisioned with large frozen juice disks. These disks share some properties with prey carcasses: they are a valued, but limited, resource; they take a considerable period of time to consume; they can be monopolized by one individual, but bits can be broken off and transferred to others. Our analyses suggest that food transfers serve multiple functions for chimpanzees. Individuals may use food transfers to enhance the welfare of closely related group members, strengthen social relationships with favoured partners and reduce the costs of persistent solicitations.
Predictive Models for Calling and Movement Activity of the Endangered Houston Toad
Donald J. Brown, Todd M. Swannack, and Michael R. J. Forstner
The American Midland Naturalist 2013 169 (2), 303-321
Anuran monitoring has increased in recent years in response to global population declines. Delineating abiotic factors that influence anuran activity patterns is important for maximizing monitoring and research efficiency. The Houston toad (Bufo (Anaxyrus)houstonensis) was the first amphibian to be listed as federally endangered in the United States, and populations have continued to decline since it was listed. In this study we investigated the influence of six abiotic factors and one biotic factor on Houston toad calling activity and terrestrial movement in the Lost Pines ecoregion of Texas. Using program PRESENCE, we treated the factors as survey-specific covariates to determine their influence on detection probabilities, and thus presumably activity levels. We found that average daily absolute humidity, average daily wind speed, and presence/absence of Houston toad calling activity the previous night were important factors influencing calling activity, and average daily absolute humidity and detection/non-detection of Houston toad movement activity the previous night were important factors influencing movement activity. We also found that multiple survey years were necessary to delineate influential factors for this species, a result with implications for activity patterns of other rare anurans. The results of this study contribute to our understanding of amphibian activity patterns, and will improve the efficiency of future Houston toad research and monitoring efforts.
Disruptive Influences of Drought on the Activity of a Freshwater Turtle
Whitney J. B. Anthonysamy, Michael J. Dreslik, and Christopher A. Phillips
The American Midland Naturalist 2013 169 (2), 322-335
Drought is an ecological challenge for turtle species worldwide and can be exacerbated by habitat fragmentation and loss, especially for small populations. We studied the activity of 16 Blanding’s turtles Emydoidea blandingii using radio-telemetry from 2005–2006 during consecutive drought and normal hydrological years at a fragmented preserve in northeastern Illinois, U.S.A. The preserve experienced drought conditions during 2005 with precipitation levels 20% below the 60 y average. Fine scale measures of activity (i.e., mean water depth at locations, proportion of unique locations, and proportion of locations in dry habitat) differed between years, whereas broad scale measures of activity (i.e., home range, movement distance) did not. On average only 41.3% of 2005 home ranges overlapped with 2006 home ranges suggesting space use shifted between years. Although most proportional habitat use remained unchanged between years, several individuals increased their use of riverine habitats when other wetland habitat dried. Our study underscores the need to examine the risks of severe environmental events on vulnerable populations.
Juvenile Alligator Gar Movement Patterns in a Disconnected Floodplain Habitat in Southeast Missouri
Levi E. Solomon, Quinton E. Phelps, David P. Herzog, Christopher J. Kennedy, and Michael S. Taylor
The American Midland Naturalist 2013 169 (2), 336-344
Telemetry is an extremely useful technique used to study movement patterns of fishes to gain insight into life history. This is especially important when dealing with species of conservation concern, such as the alligator gar (Atractosteus spatula). Alligator gar, despite dwindling populations or presumed extirpation across much of its native range, have received minimal attention in the literature. This study sought to evaluate movement patterns of juvenile alligator gar reintroduced to a historic, now disconnected, floodplain of the Mississippi River. Nineteen alligator gar fitted with radio transmitters were stocked into Mingo National Wildlife Refuge during May 2007 and tracked for 1 y. Over the course of the evaluation, 34.9 (se = 5.1) locations per individual gar were recorded and three distinct movement patterns emerged. Thirteen alligator gar (Groups A and B) exhibited site fidelity throughout the study while five alligator gar (Group C) showed highly variable movement patterns; at times showing site fidelity, then exhibiting long-distance movements. When exhibiting site fidelity, alligator gar occupied small areas of Monopoly Marsh or Ditch 5 (Group A: 12.9 ± 6.0 ha, Group B: 4.8 ± 4.9 ha, Group C: 11.8 ± 8.0 ha). Our study demonstrated telemetry of juvenile alligator gar is feasible, various movement patterns (i.e., site fidelity or long-distance movement) exist, and future stockings of juvenile alligator gar are likely to show site fidelity to the area in which they are released.
Double-crested Cormorants (Phalacrocorax auritus) of Leech Lake, Minnesota: Temporal Variation of Diets and Assessment of Differential Prey Selection in Adults
Peter J. Hundt, Andrew M. Simons, and Donald L. Pereira
The American Midland Naturalist 2013 169 (2), 354-370
In 1998, after 160 y without documented nesting, Double-crested Cormorants (Phalacrocorax auritus) recolonized Leech Lake, Minnesota. Competition for nesting space with the state threatened Common Tern (Sterna hirundo), and concern regarding potential walleye (Sander vitreus) and yellow perch (Perca flavescens) population declines prompted culling of cormorants and research into their diet. Stomach contents of adult and subadult cormorants were collected in 2004, 2005, and 2006 (186, 356 and 348, respectively) and from cormorant chick regurgitants in 2005 and 2006 (151 and 114, respectively). Perca flavescens (>70% composition and biomass) and shiner species (Notropis sp.) (>4% composition and biomass) were the main components of subadult and adult cormorant diets in 2004 and 2005 and the diet of chicks in 2005. However in 2006, whitefish species (Coregonus sp.) was the majority of percent biomass consumed by subadults and adults (43.4%) and a large proportion of percent biomass consumed by chicks (17.8%). In 2006 percent biomass of Corengonus sp. was different from other years for adults and subadults (P < 0.001) and chicks (P < 0.01) and may have been a product of a warming event die-off in late summer. All eight of the select common prey species varied (P < 0.01) in percent biomass between at least one of the ten delineated periods within 2004, 2005, or 2006. Differential prey selection by adults for self-feeding and provisioning for chicks was detected in Coregonus sp. (P < 0.01). While the diet of Leech Lake cormorants mainly consists of small abundant fish (P. flavescens and Notropis sp.), cormorant diet can vary within and among years. This study represents the first description of the diet of cormorants from a midwestern location other than the Great Lakes and reinforces the importance of site specific diet assessment, as the particular abundant prey species differs between locations.
Comparative Spring-Staging Ecology of Sympatric Arctic-Nesting Geese in South-Central Nebraska
Aaron T. Pearse, Gary L. Krapu, and Robert R.CoxJr
The American Midland Naturalist 2013 169 (2), 371-381
The Rainwater Basin in Nebraska has been a historic staging area for midcontinent greater white-fronted geese (Anser albifrons frontalis) since the 1950s and, in the mid-1990s, millions of midcontinent lesser snow geese (Chen caerulescens caerulescens) expanded their spring migration route to include this region. In response to speculation that snow geese may be in direct competition with white-fronted geese, we compared staging ecology by quantifying diet, habitat use, movement patterns, and time budgets during springs 1998–1999. Collected white-fronted geese (n = 190) and snow geese (n = 203) consumed primarily corn (Zea mays; 97–98% aggregate dry mass) while staging in Nebraska; thus, diet overlap was nearly complete. Both species used cornfields most frequently during the morning (54–55%) and wetlands more during the afternoon (51–65%). When found grouped together, snow goose abundance was greater than white-fronted goose abundance by an average of 57 times (se = 11, n = 131 groups) in crop fields and 28 times (se = 9, n = 84 groups) in wetlands. Snow geese and white-fronted geese flew similar distances between roosting and feeding sites, leaving and returning to wetland roost sties at similar times in mornings and afternoons. Overlap in habitat-specific time budgets was high; resting was the most common behavior on wetlands, and foraging was a common behavior in fields. We observed 111 interspecific agonistic interactions while observing white-fronted and snow geese. White-fronted geese initiated and dominated more interactions with other waterfowl species than did snow geese (32 vs. 14%). Certain aspects of spring-staging niches (i.e., diet, habitat use, movement patterns, and habitat-specific behavior) of white-fronted and snow geese overlapped greatly at this mid-latitude staging site, creating opportunity for potential food- and habitat-based competition between species. Snow geese did not consistently dominate interactions with white-fronted geese; yet large differences in their numbers coupled with high degrees of spatial, temporal, and ecological overlap support potential for exploitative competition during years when waste corn may be in short supply and dry years when few wetlands are available for staging waterfowl.
Comparative Occupancy and Habitat Associations of Black-and-White (Mniotilta varia) and Golden-Cheeked Warblers (Setophaga crysoparia) in the Juniper-Oak Woodlands of Central Texas
Christopher C. Warren, James R. Ott, and Joseph A. Veech
The American Midland Naturalist 2013 169 (2), 382-397
The golden-cheeked warbler (Setophaga chrysoparia) and the black-and-white warbler (Mniotilta varia) breed in the deciduous/evergreen woodlands of central Texas. The golden-cheeked warbler is endemic, while for the geographically widespread, black-and-white warbler, these woodlands represent the southwestern terminus of the breeding range. To estimate relative abundance and to compare habitat associations, we estimated occupancy, corrected for probability of detection, for both species using replicated point-count surveys of 36 survey stations at each of six sites within the Balcones Canyonlands Preserve Travis Co. TX. Model selection using an a priori, set of candidate models suggested that the probability of detection differed among warbler species and study sites and both species were influenced by time of season, time of day, and habitat characteristics of the survey station—slope and canopy cover. Naïve occupancy estimates suggested that occupancy of black-and-white warblers was much lower than golden-cheeked warblers. However model-averaged estimates of occupancy corrected for imperfect detection suggested that occupancy of black-and-white warblers averaged across all study sites and survey stations were comparable to golden-cheeked warblers. For both black-and-white and golden-cheeked warblers occupancy was positively influenced by slope and this relationship was modulated by canopy cover. Our study provides an example of how occupancy modeling can change naïve perceptions of the relative abundance of species and be used to predict habitat associations of animals through point-count surveys while accounting for imperfect detection.
Where Are the Bluebirds of the Bluegrass? Eastern Bluebird Decline in Central Kentucky
Daniel P. Wetzel and James J. Krupa
The American Midland Naturalist 2013 169 (2), 398-408
Eastern bluebird (Sialia sialis) populations are increasing across most of the species‘ range; however, we document a decline in a bluebird population in central Kentucky, where state and local Christmas Bird Count and Breeding Bird Survey data indicate bluebirds are declining throughout the Ohio River valley region. We examined several possible hypotheses for this decline, including habitat loss, nest cavity loss, increased competition from other species, and variation in winter temperature using long term nesting data gathered at one study site in central Kentucky. We found that bluebird abundance was positively correlated with mean temperature during the previous winter. Our data suggest bluebirds in central Kentucky are declining because they are susceptible to cold winters and are experiencing increased nest box competition.
Is the Coyote (Canis latrans) a Potential Seed Disperser for the American Persimmon (Diospyros virginiana)?
Katherine Roehm and Matthew D. Moran
The American Midland Naturalist 2013 169 (2), 416-421
The role of carnivores in seed dispersal has only recently been studied in North American plants. We investigated the potential effectiveness of the Coyote (Canis latrans) as a seed disperser for American Persimmon (Diospyros virginiana; Ebenaceae) and tested the effect of experimental design in gut passage experiments. Germination percentage and rate and vigor of seedlings produced by D. virginiana seeds collected from Coyote scat were compared to seeds removed from or contained in whole fruit in a common garden experiment. Germination percentages for Coyote ingested seeds and whole fruit were nearly the same. Emergence was significantly faster for seedlings produced from ingested seeds compared to those seeds in whole fruit, however the quality of these seedlings was significantly poorer. Seedlings produced by seeds artificially removed from fruits had greater survival than those resulting from seeds ingested by coyotes or contained in intact fruits. Our results suggest that Coyotes can effectively disperse D. virginiana,but whether the positive aspects of dispersal outweigh the negative effects of gut passage remains an open question. Our experimental results indicate that these two species have not coevolved, as expected, since the range of Coyotes has only recently overlapped substantially with that of D. virginiana.
Prairie Dog Aboveground Aggressive Behavior Towards Black-footed Ferrets
Travis M. Livieri, Daniel S. Licht, Brendan J. Moynahan, and Patrick D. Mcmillan
The American Midland Naturalist 2013 169 (2), 422-425
Black-footed ferrets typically prey upon prairie dogs at night while prairie dogs are presumably sleeping. Prairie dogs can act aggressively towards aboveground ferrets in daylight and we observed prairie dog aggression towards ferrets four times in South Dakota and Montana. Ten behaviors by prairie dogs were recorded during aggressive interactions with ferrets including chasing, blocking, and physical contact. One of the aggressive prairie dogs was confirmed as an adult male and three of four encounters occurred Jun. through Jul. Interactions lasted
Potential for Bias in Using Hybrids Between Common Carp (Cyprinus carpio) and Goldfish (Carassius auratus) in Endocrine Studies: A First Report of Hybrids in Lake Mead, Nevada, U.S.A
Steven L. Goodbred, Reynaldo Patiño, Erik Orsak, Prakash Sharma, and Shane Ruessler
The American Midland Naturalist 2013 169 (2), 426-431
During a 2008 study to assess endocrine and reproductive health of common carp (Cyprinus carpio) in Lake Mead, Nevada (U.S.A.) we identified two fish, one male and one female, as hybrids with goldfish (Carassius auratus) based on morphology, lateral line scale count, and lack of anterior barbels. Gross examination of the female hybrid ovaries indicated presence of vitellogenic ovarian follicles; whereas histological evaluation of the male hybrid testes showed lobule-like structures with open lumens but without germ cells, suggesting it was sterile. Because common carp/goldfish hybrids are more susceptible to gonadal tumors and may have different endocrine profiles than common carp, researchers using common carp as a model for endocrine/reproductive studies should be aware of the possible presence of hybrids.
J. Filloy, M.I. Bellocq, Spatial variation in bird species abundances: Environmental constraints across southern Neotropical regions, Basic and Applied Ecology, Available online 23 March 2013, ISSN 1439-1791, 10.1016/j.baae.2013.02.007.
Climate and habitat type are frequently related with the abundance of individual species and have been hypothesized to be primary drivers of the spatial variation in species abundances at the regional scale. Our aim is to evaluate the relative roles of those environmental factors in determining spatial variation in bird species abundance. We surveyed birds and habitat-cover variables and compiled climatic data along a 1700-km latitudinal gradient in the southern Neotropics. To identify the primary environmental variable explaining spatial changes in species abundances we performed simple regressions; a goodness of fit test identified the environmental factor that most frequently acted as the primary predictor. Mantel tests and partial regressions were performed to account for the spatial structure of abundance and environmental factors and collinearity between them. Of the 88 species included, 70% responded primarily to habitat cover and the remaining to climate. Forest cover and annual thermal amplitude were the main habitat-cover and climatic variables, respectively, explaining spatial variation in bird abundances. Our results indicated that the considered environmental factors accounted for latitudinal changes in species abundances; however, habitat cover and climate together explained a higher proportion of the variation than each factor independently of each other. There was a primacy of habitat-cover type over climate to predict spatial changes in bird species abundances across the neotropical biogeographic regions studied, but the underlying causes are likely related with the interaction of both factors.