Fernando A. Cervantes

Home Range and Social Behavior of the Endangered Tehuantepec Jackrabbit (Lepus flavigularis) in Oaxaca, Mexico

Abstract We studied the home-range and core-area size and overlap of Tehuantepec jackrabbits (Lepus flavigularis) by radiotracking 32 individuals between May 2001 and April 2003 in savanna habitat in the Isthmus of Tehuantepec, Oaxaca, Mexico. Annual home-range and core-area sizes averaged 55 ha ± 8 SE and 8 ± 1 ha for 10 adults of both sexes using the 95% and 50% fixed-kernel isopleths, respectively. Seasonal home ranges varied widely for adults, from 15 to 111 ha for females and from 24 to 166 ha for males. Juvenile males had larger seasonal home ranges than did juvenile females (X̄ = 80 and 24 ha). For adult jackrabbits, seasonal home ranges were larger during the 1st year compared to those of the 2nd year of study (X̄ = 87 and 49 ha), particularly for females. Home ranges and core areas of Tehuantepec jackrabbits were comparable in size and overlapped between active periods (nocturnal and crepuscular hours) and inactive periods (diurnal hours). Adults overlapped their home ranges with 1–10 individuals. Home-range overlap among females was greater than among males. Females shared portions of their ranges with other females more frequently than did males with other males. Home-range and overlap analysis suggests that Tehuantepec jackrabbits have polygamous mating behavior and nonterritorial social organization.

Genic Differentiation and Phylogenetic Relationships among Tropical Harvest Mice (Reithrodontomys: Subgenus Aporodon)

Abstract To assess genic differentiation and phylogenetic relationships among selected species in the subgenus Aporodon, we screened 31 presumptive genetic loci in 6 species in the subgenus Aporodon (R. creper, R. gracilis, R. mexicanus, R. microdon, R. spectabilis, and R. tenuirostris) and in 4 species in the subgenus Reithrodontomys (R. chrysopsis, R. fulvescens, R. megalotis, and R. sumichrasti). The resulting phylogenetic trees were compared with the results of previous molecular and morphological studies. Results demonstrate that the subgenus Aporodon is monophyletic. Relationships determined on the basis of allozymes are largely congruent with an earlier analysis based on morphological and molecular characters. However, samples of R. mexicanus do not form a monophyletic lineage. Accordingly, populations from north-central Oaxaca and Costa Rica each likely represent an undescribed species.

NEW RECORDS OF MAMMALS FROM HIDALGO AND GUERRERO, MEXICO

Abstract This paper reports the first record of the bats Enchisthenes hartii and Natalus stramineus in the state of Hidalgo and of the rodent Nyctomys sumichrasti in the state of Guerrero, Mexico. These records increase the known range of these species. External and cranial measurements and reproductive condition of the specimens are reported. We also include the habitat where they were captured and the presence therein of other small mammals.

NEW RECORDS OF THE ENDANGERED TEHUANTEPEC JACKRABBIT (LEPUS FLAVIGULARIS) FROM OAXACA, MEXICO

Abstract We obtained new records of the Tehuantepec jackrabbit, Lepus flavigularis, in the state of Oaxaca, México. The records represent 3 new populations of L. flavigularis in the southern part of the Isthmus of Tehuantepec. The total area where the new records of L. flavigularis occurred is 67 km2. It is necessary to conduct additional studies to obtain details of the actual distribution of the endangered L. flavigularis and recommend actions for its conservation.

PARENTAL BEHAVIOR OF THE VOLCANO MOUSE, NEOTOMODON ALSTONI (RODENTIA: MURIDAE), IN CAPTIVITY

Abstract Paternal behavior of the volcano mouse (Neotomodon alstoni) was studied and its role in the care of young compared with that of the female. Paternal behavior of this rodent under laboratory conditions consisted of direct and indirect activities, such as huddling, grooming, sniffing, and retrieving young as well as maintenance and vigilance of the nest. The male volcano mouse exhibited all components of parental behavior displayed by mothers, except suckling. However, the male participated significantly more than the female in huddling, grooming, and sniffing. The existence of paternal behavior in this rodent suggests that under natural conditions this species exhibits a monogamous mating system because monogamy in rodents is often associated with paternal care.

Molecular systematics of small-eared shrews (Soricomorpha, Mammalia) within Cryptotis mexicanus species group from Mesoamérica

Cryptotis mexicanus species group is the most diverse group of Cryptotis shrews in the Mesoamerican highlands (ca.13 species). In México, eight endemic species occurs and several taxa are endangered. The species’ limits and phylogenetic relationships of these taxa have been recently examined using morphology; nevertheless, little is known about phylogenetic relationships among Cryptotis species at the molecular level. Therefore, our research included a mitochondrial DNA marker as a source of additional information to corroborate taxonomic identification and produce a phylogenetic hypothesis of the C. mexicanus species group. We were particularly interested in the status of Cryptotis magnus, a species considered as relict on the basis of primitive characters. Based on the analyses of genetic sequences of a high number of Cryptotis species, outgroups, and phylogenetic analyses of parsimony and Bayesian inference, we confirmed that Cryptotis genus consists of different lineages that represent species groups. A detailed analysis suggests that C. magnus is a species that shares an evolutionary history with the C. mexicanus species group because it is imbedded within this group. In particular, our data strongly support that C. magnus and Cryptotis phillipsii are sister groups, a pair of species that inhabit allopatrically Southern México.

REPRODUCTION OF BLACK-TAILED JACKRABBITS (LAGOMORPHA: LEPUS CALIFORNICUS) IN RELATION TO ENVIRONMENTAL FACTORS IN THE CHIHUAHUAN DESERT, MEXICO

Abstract Climatic elements can influence reproduction of mammals. In temperate zones, reproduction often is related to favorable environmental factors, such as spring and rainy seasons, which correspond to availability of food. The goal of this study was to describe the reproductive cycle of the black-tailed jackrabbit, Lepus californicus, with regards to temperature, rainfall, evaporation, and photoperiod in the Mapimí Biosphere Reserve in the central Chihuahuan Desert, Durango, Mexico. If the onset of breeding correlates with these environmental factors, we predicted that mating should be related to total rainfall. To test this prediction, we collected 39 females and 36 males between July 1996 and November 1997 and measured and recorded reproductive condition. Weights of ovaries in females were correlated with increases in photoperiod, evaporation, rainfall, and mean monthly temperature. Increases in male testicular weight were correlated with increasing photoperiod only. We concluded that differences in responses of males and females were related to differing reproductive strategies. Females experience higher reproductive costs and probably respond to a more complex set of environmental cues to increase their reproductive success.

NEST-SITE SELECTION BY THE MEXICAN RED-BELLIED SQUIRREL (SCIURUS AUREOGASTER) IN MICHOACÁN, MEXICO

Abstract Nests are important structures for the reproduction and survival of many organisms. We studied nest-site selection by the Mexican red-bellied squirrel (Sciurus aureogaster) in an oak–pine forest located south of Pátzcuaro, Michoacán, Mexico. We quantified 20 habitat characteristics and 6 nest characteristics for a total of 90 nest sites. Nest sites were compared with 90 random sites in parts of the forest where we always found nests (availability), and with 90 random sites in portions of the study area where we never located nests (unused sites). Nests were built in the tallest and largest trees and close to the main trunk. Unused sites are limiting the nesting capacity of squirrels apparently because these sites maintain a lower density of trees compared with nest sites. Two of the 6 characteristics quantified for nests were significantly associated with habitat characteristics where squirrels built nests. Quercus candicans was the tree species most widely used for nesting during the wet season, whereas Q. laurina was commonly used in the dry season, apparently in relation to the periods of mast production.

Food Habits of the Rabbit Romerolagus diazi (Leporidae) in Central México

Fecal pellets of Romerolagus diazi collected biweekly during 1 year from a permanent plot in central Mexico were examined to determine the diet of this leporid. Muhlenbergia macroura, Stipa ichu , and Alnus arguta were staple food items. The annual intake of forbs was low and mostly occurred during the dry season, especially in spring. Grasses were important during all seasons, especially during the wet period. Trees were consumed in similar proportions during the dry and wet periods, and the consumption of shrubs increased during the harsh conditions of the dry season. Similar to other leporids, R. diazi consumed woody plants, particularly shrubs, in high proportions during the cold and dry conditions of winter. Grasses were important for cover and nest material, and provided a significant food source for R. diazi .

Home Range Size and Activity Patterns of Bobcats (Lynx rufus) in the Southern Part of their Range in the Chihuahuan Desert, Mexico

Abstract Home range size, daily travel distances, and diel activity patterns are important characteristics of how an animal uses its home range area. In species, such as the bobcat (Lynx rufus), with large geographical ranges, it is necessary to gather data on diverse populations across the range to better understand what might be factors influencing these home range parameters. Although there are many studies of bobcats in more northern areas of its range in the United States, few data exist from its extensive southern range in Mexico. To fill this gap in information, we collected data on home range size, daily travel distances, and diel activity patterns of bobcats from the center of the Chihuahuan Desert in Mexico. We compared our findings with available data from more northern studies and tested for any latitudinal trends in home range size. We trapped eight adult bobcats (four females and four males) between 2006 and 2008 at the Mapimi Biosphere Reserve in the Chihuahuan Desert. Each bobcat was equipped with a GPS radio collar that estimated their location and ambient temperature every half hour at night (1900 to 800 h), and every hour during the day (800 to 1900 h). These data were used to estimate total daily distance traveled, average speed, home range size, activity pattern, and to test for an association between hourly travel and ambient temperature. For bobcats in Mapimi, mean distances traveled daily (4.9 ± 0.7 km), mean speed (0.3 ± 0.4 km/h) and average home range size (25.9 km2 ± 3.7) did not differ from other places in U.S. (distance traveled daily 5.7 ± 1.4 km, mean speed 0.4 ± 0.4 km/h and home range size 34.0 ± 5.4 km2). Bobcats are most active from 1700 to 2300 h and from 0500 to 1200 h and showed a minimum activity period from 1300 to 1600 h. These patterns did not differ from what other studies found. Distance traveled was inversely correlated with environmental temperature (r2  =  0.506, P < 0.05). Our data demonstrate that most behaviors of bobcats in this hot desert environment did not differ in general from their more northern populations. Although our home range estimates were similar to other studies, our analysis did support a latitudinal decreasing trend that indicates factors other than those related to latitude are affecting home range size in bobcats. We suggest investigating other independent factors not related with latitude such as primary production and rainfall might help identify which, if any, of these factors contribute to home range size in bobcats.