Evolutionary loss of a signalling colour is linked to increased response to conspecific chemicals

Behavioural responses to communicative signals combine input from multiple sensory modalities and signal compensation theory predicts that evolutionary shifts in one sensory modality could impact the response to signals in other sensory modalities. Here, we conducted two types of field experiments with 11 species spread across the lizard genus Sceloporus to test the hypothesis that the loss of visual signal elements affects behavioural responses to a chemical signal (conspecific scents) or to a predominantly visual signal (a conspecific lizard), both of which are used in intraspecific communication. We found that three species that have independently lost a visual signal trait, a colourful belly patch, responded to conspecific scents with increased chemosensory behaviour compared to a chemical control, while species with the belly patch did not. However, most species, with and without the belly patch, responded

Evaluation of pocket gopher diet in a perennial productive area

The desert pocket gopher (Geomys arenarius) is a fossorial herbivorous rodent of the family Geomyidae. Its distribution range is restricted to New Mexico and Texas, in the United States of America, and northern Chihuahua, in México. The Médanos de Samalayuca Flora and Fauna Protection Area (MSFFPA) is located in northern Chihuahua. Different economic activities are carried out in this region, mainly irrigated crops of pecans (Carya illinoinensis). Populations of G. arenarius have been recorded within these areas. Therefore, the objective of this work was to define the extent of the trophic niche and the changes in the physical condition of G. arenarius in a ranch within the MSFFPA over three contrasting seasons (dry, wet, and post-wet). Forty G. arenarius specimens were collected from Arantxa Ranch. Morphometric measurements and the weight of collected individuals were recorded, and the digestive tract was removed to prepare histological slides. Seven 25 m²-quadrants were established, and the species of the vegetation cover were recorded and collected for reference. The Seasonal Fitness Index (IK) and Levin’s Niche Breadth Index were calculated. Males had higher average measurements and weight than females. The IK was 2.82 ± 0.47 in males and 2.64 ± 0.61 in females. Significant differences in the IK between seasons were only found in females. The correlation between IK and plant cover was strong for males and females. The diet mainly comprised Physalis hederifolia, Dimorphocarpa wislizeni, and Cenchrus incertus. Levin’s index showed that G. arenarius is a specialist rodent. Sexual dimorphism was evident, with males larger than females. The physical condition index of gophers is influenced by resource availability. In other studies, this parameter has been related to changes in food availability. It has been reported that gophers tend to feed mainly on crops; however, pecan cultivation was not a major element in the diet of the desert pocket gopher, as it feeds on the vegetation associated with crops. Gophers are considered generalists; nonetheless, the present study showed that G. arenarius is a specialist, although this may be a consequence of anthropogenic activities

New species of flea of the genus Dactylopsylla Jordan (Insecta: Siphonaptera) from the Flora and Fauna Protection Area Médanos de Samalayuca, Chihuahua, Mexico

A new species of Dactylopsylla Jordan, parasites of Geomyidae rodents from Chihuahua, is described and illustrated as D. samalayucae n. sp. This species is compared with their morphologically closest relatives. Males are characterized by the shape of the upper lobe of the inmovable and movable process, the shape and chaetotaxy of the distal arm of sternum IX and the shape of the crochet; and females by the contour of the distal margin of sternum VII. The geographical distribution of Dactylopsylla is extended to the Chihuahuan desert in Mexico as D. samalayucae n. sp. is reported from south of the Natural Protected Area Médanos de Samalayuca (MS). A recent key to Dactylopsylla species is updated with inclusion of the new species

Riparian biota of the Protected Area of Flora and Fauna Santa Elena Canyon, Mexico

The Protected Area of Flora and Fauna Santa Elena Canyon (Chihuahua, Mexico) has a national and international importance due to its flora and fauna, the contrast of its ecosystems and landscape resources, fostering a concern for its conservation. The objective of this study was to register species of birds, land mammals, fish and vegetation of the riparian zone at three locations within the protected area. Birds monitoring was conducted by no fixed radius count points, Sherman traps, trail cams and transect lines were used for land mammals, fish were monitored using manual fishing techniques and fishing spoon nets and finally the vegetation was recorded by means of interception lines. Field work was performed from December 2017 to December 2018. Among the four biological groups, a total of 166 species were recorded. Fauna: 73 birds, 24 land mammals and two fish species; flora: 67 species. Of the species we found 13.85 % are listed in the NOM-059-SEMARNAT-2010; 69.87 % were listed on the IUCN Red List of Threatened Species and 34 species were not included within the Management Program of the area. This study highlighted the need for systematic monitoring to increase knowledge and promote the conservation of the Protected Area of Flora and Fauna from Santa Elena Canyon in the future

Disentangling an avian assemblages’ evolutionary and functional history in a Chihuahuan desert city

Urban green spaces have been shown to be important hotspots of biodiversity in cities of temperate and humid/semihumid tropical ecoregions. Nonetheless, whether this pattern applies to urban ecosystems of desert environments has been rarely studied. Temperature, precipitation, vegetation complexity, human density, and presence of invasive species could act as urban filters limiting the incidence of desert-adapted species into cities. Such effects could be reshaping biotic communities, favoring habitat generalist species in human-dominated environments. In this study, we examined the phylogenetic and functional structure of avian assemblages in a Chihuahuan desert city and its surroundings to infer the processes underlying community assembly. We used phylogenetic comparative methods to test the hypothesis whether there is an underlying pattern determining which desert-adapted species penetrate or tolerate a novel urban ecosystem. We also performed a regression approach to determine which environmental and anthropogenic variables may be associated with these metrics. We found that urban green spaces present more evolutionary and functional diversity (based on the proportion of total tree branch length) than agricultural fields and desert scrub, although not statistically significant. On the other hand, based on the mean branch length distance among sample taxa, we observed clustered communities suggesting environmental filtering. Most continuous functional traits presented a low and significant phylogenetic signal, but nearly all binary traits were conserved across phylogeny. Phylogenetic predisposition to be a habitat generalist is present in the surveyed avian assemblages. Our regression analysis indicates that invasive bird species richness was negatively correlated with net relatedness index (NRI) and functional net relatedness index (FNRI), while functional diversity metrics were influenced by temperature and precipitatio

First report of Siphonaptera parasites in Canis latrans in the Flora and Fauna Protection Area, Médanos de Samalayuca Chihuahua, Mexico

Siphonaptera are hematophage parasite vectors of both human and animal diseases. We aimed to identify ectoparasites parasitizing a coyote population (Canis latrans) in the northwest region of the Flora and Fauna Protection Area Médanos de Samalayuca, Chihuahua, Mexico. We captured 21 coyotes (15 males and 6 females) during the summer and winter of 2018. The individuals were anesthetized and thoroughly examined for ectoparasites. We found that 43% of the coyotes were infested. Based on characteristics such as the absence of pronotal and genal combs in the head, we identified 15 specimens as Pulex irritans. This is the first report of P. irritans in coyotes in Médanos de Samalayuca Chihuahua, Mexico

Losing the trait without losing the signal: Evolutionary shifts in communicative colour signalling

Colour signalling traits are often lost over evolutionary time, perhaps because they increase vulnerability to visual predators or lose relevance in terms of sexual selection. Here, we used spectrometric and phylogenetic comparative analyses to ask whether four independent losses of a sexually selected blue patch are spectrally similar, and whether these losses equate to a decrease in conspicuousness or to loss of a signal. We found that patches were lost in two distinct ways: either increasing reflectance primarily at very long or at very short wavelengths, and that species with additional colour elements (UV, green and pink) may be evolutionary intermediates. In addition, we found that patch spectral profiles of all species were closely aligned with visual receptors in the receiver's retina. We found that loss of the blue patch makes males less conspicuous in terms of chromatic conspicuousness, but more conspicuous in terms of achromatic contrast, and that sexual dimorphism often persists regardless of patch loss. Dorsal surfaces were considerably more cryptic than were ventral surfaces, and species in which male bellies were the most similar in conspicuousness to their dorsal surfaces were also the most sexually dimorphic. These results emphasize the consistent importance of sexual selection and its flexible impact on different signal components through evolutionary time

Volatile fatty acid and aldehyde abundances evolve with behavior and habitat temperature in Sceloporus lizards

Animal signals evolve by striking a balance between the need to convey information through particular habitats and the limitations of what types of signals can most easily be produced and perceived. Here, we present new results from field measures of undisturbed behavior and biochemical analyses of scent marks from 12 species of Sceloporus lizards to explore whether evolutionary changes in chemical composition are better predicted by measures of species behavior, particularly those associated with visual displays, chemoreception, and locomotion, or by measures of habitat climate (precipitation and temperature). We found that more active lizard species used fewer compounds in their volatile scent marks, perhaps conveying less specific information about individual and species identity. Scent marks from more active lizard species also had higher proportions of saturated fatty acids, and the evolution of these compounds has been tracking the phylogeny closely as we would expect for a metabolic byproduct. In contrast, the proportions of unsaturated fatty acids were better explained by evolutionary shifts in habitat temperature (and not precipitation), with species in warmer climates using almost no volatile unsaturated fatty acids. The proportion of aldehydes was explained by both behavior and environment, decreasing with behavioral activity and increasing with habitat temperature. Our results highlight the evolutionary flexibility of complex chemical signals, with different chemical compounds responding to different elements of the selective landscape over evolutionary time

Molecular identifcation and morphological variations of Dermacentor albipictus collected from two deer species in northern Mexico

In total, 57 ticks were collected from six white-tailed deer (Odocoileus virginianus) and three mule deer (O. hemionus) in northern Mexico during the 2017, 2018 and 2019 hunting seasons. Morphological features of adult male and female ticks were observed and photographed using a stereo-microscope and scanning electron micrography. The ticks were identifed as Dermacentor albipictus based on taxonomic keys. Molecular analysis using DNA amplifcation of the 16S rDNA and cytochrome oxidase 1 (COI) genes was employed to resolve the phylogenetic relationships from 18 strains of Dermacentor species. Bayesian phylogenetic analysis was performed in order to obtain a phylogenetic tree based on the concatenated sequence in the D. albipictus clade. The geometric morphometric analysis compared the body shape of ticks collected from specimens of two deer species by analyzing nine dorsal and ventral landmarks from both males and females. The results suggest that body shape variation in dorsal structures might be related to the host

Data for Ossip-Drahos et al. 2016

Mean spectrophotometric measures and Just-noticeable-differences estimated for bellies of males and females of four species of Sceloporus lizards