Roads, routes and rams: does sexual segregation contribute to anthropogenic risk in a desert-dwelling ungulate?

2016 ◽  
Vol 43 (5) ◽  
pp. 380 ◽  
Author(s):  
Vernon C. Bleich ◽  
Jericho C. Whiting ◽  
John G. Kie ◽  
R. Terry Bowyer

Context Little is known about the consequences of sexual segregation (differential use of resources by the sexes outside of the mating season) for the conservation of large mammals. Roadways (i.e. the strip of land over which a road or route passes) are ubiquitous around the world, and are a major cause of wildlife mortality, as well as habitat loss and fragmentation. Many populations of bighorn sheep (Ovis canadensis) occur at low densities and in a metapopulation structure. Roadways could affect movements of males and females differentially, an outcome that has not been considered previously. Aims We investigated the propensity of the sexes to cross a paved two-lane road and a single-lane, maintained dirt route and predicted that adult males, because of their life-history characteristics, would cross those roadways more often than females. Methods We investigated movements of male and female bighorn sheep from 1986 to 1990. We used a fixed-wing aircraft with an H-antenna on each wing strut to locate individuals each week from October 1986 to December 1990. We estimated the degree of overlap among 50% core areas of use by males and females with the utilisation distribution overlap index (UDOI). Key results We relocated male and female bighorn sheep on 948 occasions during sexual aggregation and on 1951 occasions during sexual segregation. More males than females were likely to cross both types of roadways during segregation, and the dirt route during aggregation. Propensity of males and females to cross roadways was strongly influenced by time of year (i.e. whether the period of sexual aggregation or sexual segregation). The lowest overlap in 50% core areas was between females and males during periods of segregation (UDOI = 0.1447). Conclusions More males than females crossed Kelbaker Road and the unnamed dirt route during segregation, as well as the unnamed route during aggregation. Both of those features could affect males more than females, and could result in reductions in the use of habitat or increased mortality of bighorn sheep from vehicle collisions as a result of spatial segregation of the sexes. Implications During environmental review, biologists should consider sexual segregation when assessing potential anthropogenic effects on movements of bighorn sheep. Biologists also should consider sexual segregation and how roadways, even lightly traveled routes, affect movements of male and female ungulates differently before manipulating habitat, translocating animals, or constructing or modifying roadways.

1967 ◽  
Vol 56 (1) ◽  
pp. 165-176 ◽  
Author(s):  
Donald C. Johnson

ABSTRACT Ventral prostates in hypophysectomized male parabiotic partners of intact animals were used to compare the amount of plasma luteinizing hormone (LH) in males and females of various ages. Ovarian weight, histology, and augmentation with chorionic gonadotrophin, in hypophysectomized androgenized females were used to estimate plasma follicle stimulating hormone (FSH) activity in intact adult males and females. In young animals, up to 50 days of age, males apparently have the same amount of plasma LH as females, but older cyclic females produced significantly heavier prostates in their hypophysectomized male partners than did males. The results are consistent with the interpretation that cyclic surges of LH added to a tonic level produced an average value higher for females than males. In contrast, males of all ages and particularly adults, have a significantly greater amount of circulating FSH than females.


2012 ◽  
Vol 102 (4) ◽  
pp. 453-460 ◽  
Author(s):  
M. Gołębiowski ◽  
M. Paszkiewicz ◽  
A. Grubba ◽  
D. Gąsiewska ◽  
M.I. Boguś ◽  
...  

AbstractThe composition of cuticular and internal n-alkanes in Lucilia sericata larvae, pupae, and male and female imagines were studied. The cuticular and internal lipid extracts were separated by HPLC-LLSD, after which the hydrocarbon fraction was identified by GC/MS in selected ion monitoring (SIM) and total ion current (TIC) modes.The cuticular lipids of the larvae contained seven n-alkanes from C23 to C31. The major n-alkane in L. sericata larvae was C29 (42.1%). The total cuticular n-alkane content in the cuticular lipids was 31.46 μg g−1 of the insect body. The internal lipids of L. sericata larvae contained five n-alkanes ranged from C25 to C31. The most abundant compound was C27 (61.71 μg g−1 of the insect body). Eighteen n-alkanes from C14 to C31 were identified in the cuticular lipids of the pupae. The most abundant n-alkanes ranged from C25 to C31; those with odd-numbered carbon chains were particularly abundant, the major one being C29:0 (59.5%). Traces of eight cuticular n-alkanes were present. The internal lipids of L. sericata pupae contained five n-alkanes, ranging from C25 to C31. The cuticular lipids of female imagines contained 17 n-alkanes from C12 to C30. Among the cuticular n-alkanes of females, C27 (47.5%) was the most abundant compound. Four n-alkanes, with only odd-numbered carbon chains, were identified in the internal lipids of females. The lipids from both sexes of L. sericata had similar n-alkane profiles. The cuticular lipids of adult males contained 16 n-alkanes ranging from C13 to C31. C27 (47.9%) was the most abundant cuticular n-alkanes in males. The same n-alkanes only with odd-numbered carbon chains and in smaller quantities of C27 (0.1%) were also identified in the internal lipids of males.The highest amounts of total cuticular n-alkanes were detected in males and females of L. sericata (330.4 and 158.93 μg g−1 of the insect body, respectively). The quantities of total cuticular alcohols in larvae and pupae were smaller (31.46 μg g−1 and 42.08 μg g−1, respectively). The internal n-alkane contents of larvae, pupae, and male and female imagines were significantly higher than the cuticular n-alkane contents (153.53, 99.60, 360.06 and 838.76 μg g−1 of the insect body, respectively).


2018 ◽  
Author(s):  
Munmun Chowdhury ◽  
Chun-Feng Li ◽  
Zhen He ◽  
Yuzhen Lu ◽  
Xusheng Liu ◽  
...  

AbstractThe Drosophila melanogaster Toll-Spätzle pathway plays an important role in development and immunity. Drosophila genome encodes nine Toll receptors and six Spätzle (Spz) proteins, and only the canonical Toll-Spz (Toll-1-Spz-1) pathway has been well investigated. In this study, we compared the nine Drosophila Tolls and showed that similarly to Toll, Toll-7 also strongly activated drosomycin promoter. Importantly, we showed that both Toll and Toll-7 interacted with Spz, Spz-2 and Spz-5, and co-expression of Toll or Toll-7 with Spz, Spz-2 and Spz-5 activated the drosomycin promoter. Furthermore, Toll and Toll-7 both recognized vesicular stomatitis virus (VSV) by binding to the VSV glycoprotein. Septic infection in Toll and Toll-7 mutant flies suggested that Toll and Toll-7 differentially affected defense responses in adult males and females after systemic infection by Enterococcus faecalis, Pseudomonas aeruginosa, Candida albicans or VSV. Our results suggest multiple Toll family members activate the expression of antimicrobial peptides. Our results also provide evidence that Toll and Toll-7 bind multiple Spätzle proteins and differentially affect immune defense against different pathogens in adult male and female flies.


1992 ◽  
Vol 19 (2) ◽  
pp. 137 ◽  
Author(s):  
GW Arnold ◽  
DE Steven ◽  
A Grassia ◽  
J Weeldenburg

The home ranges were studied from 1977 to 1981 of western grey kangaroos (Macropus fuliginosus) living in a 300-ha remnant of wandoo [Eucalyptus wandoo] surrounded by farmland at Baker's Hill, Western Australia. The M. fuliginosus population varied from 140 to 200 animals during the study. In 1979, four females (>30 kg) and 2 adult males (31 kg and 47 kg) were fitted with radio-transmitters and their movements recorded. The home ranges of these animals varied from 39 to 70 ha; the average overlap in the area used during the day and that used at night was 16.4%. Many of the kangaroos fed on farmland at night. The night ranges of 51 marked kangaroos were recorded using a spotlight. The animals showed a strong fidelity to their home ranges. Only 3 males (about 5-yr-old) shifted their night ranges; the centres of the ranges moved only 600-800 m. Older males had significantly larger night ranges than younger males and females. Individual females and the younger males showed preferences for using particular access points to get onto farmland; the older males showed no preferences. The core areas of the night ranges of many adult females overlapped closely in 'groups', but there was no evidence of 'mob' home ranges that were socially separated.


1977 ◽  
Vol 55 (11) ◽  
pp. 1802-1810 ◽  
Author(s):  
Valerius Geist ◽  
R. G. Petocz

In bighorn sheep (Ovis canadensis canadensis) the segregation of adult males from females is explained by two hypotheses: first, males exhausted by the rut must avoid females to escape culling predators; second, males ought to segregate from females in such a fashion as to minimize competition and disturbance for the mothers of their prospective offspring. Only the second hypothesis coincides closely with previously known facts about sheep. It predicts that on common winter ranges adult males ought to minimize competition for females by segregating spatially and by habitat selection. This was verified. Although both sexes may occupy a continuous range, they concentrate in different areas; rams have a greater preference for open slopes and ewes for cliffs. This segregation held true even in a winter with exceptional snow depths. Sheep occupied the wintering area in a similar manner in successive years; females were found to be more affected by snow than males. In their habitat preference, rams and ewes acted in accordance with their behavioural types, much as was found to be true for their social behaviour.


2013 ◽  
Vol 91 (8) ◽  
pp. 640-647 ◽  
Author(s):  
Veronika Ledvenyiova ◽  
Dezider Pancza ◽  
Jana Matejiková ◽  
Miroslav Ferko ◽  
Iveta Bernatova ◽  
...  

Sex and aging represent important factors that determine morbidity and mortality due to cardiovascular diseases in the human population. This study aimed to investigate the impact of aging on the response to ischemia–reperfusion in male and female rat hearts, and to explore a potential role of the PI3K–Akt pathway in the cardioprotective effects of ischemic preconditioning (IPC) in the myocardium of younger and older adult males and females. Langendorff-perfused nonpreconditioned and preconditioned hearts of 12- and 18-week-old male and female Wistar rats were subjected to regional ischemia and reperfusion with or without prior perfusion with the PI3K inhibitor wortmannin for the evaluation of ischemia-induced arrhythmias and the size of myocardial infarction (infarct size; IS). Aging did not modify IS in both sexes; however, it markedly increased susceptibility to arrhythmias. Although IPC effectively reduced IS in males and females of both ages, only the hearts of males and 18-week-old females benefited from its antiarrhythmic effect. In the preconditioned 12-week-old females, but not the 18-week-old females, and in males of both ages, wortmannin blunted the anti-infarct effect of IPC. In conclusion, activation of the PI3K–Akt pathway plays an important role in protection against lethal injury conferred by IPC in males irrespective of age. The IS-limiting effect of IPC appears to be PI3K–Akt-dependent only in the 12-week-old females.


1996 ◽  
Vol 74 (2) ◽  
pp. 330-342 ◽  
Author(s):  
Marco Festa-Bianchet ◽  
Wendy J. King ◽  
Jon T. Jorgenson ◽  
Kirby G. Smith ◽  
William D. Wishart

Individually marked bighorn sheep (Ovis canadensis) were monitored to determine how seasonal and lifetime changes in mass affected the development of sexual dimorphism, and to what extent mass at a given age could predict mass of the same sheep at a later age. We trapped sheep from late May to early October each year from 1971 to 1985 in a population artificially kept at low density. Lambs and yearlings gained mass linearly from June to September, while absolute mass gain of older sheep was faster in June–July than in August–September. Males gained more mass than females each summer up to at least 3 years of age. Relative summer mass gain, calculated as a proportion of body mass at the beginning of June, was the same for male and female lambs but was greater for male than for female yearlings and 2-year-olds. With the exception of lambs, all age-classes lost mass during winter. Mass loss between September 15 and June 5 was greater for females than for males, possibly because ewes lost mass through parturition in late May. For both sexes, asymptotic mass was not reached until at least 7 years of age. Mass at 4 and 12 months of age was correlated with mass at 4 years. For all sex–age classes, mass on June 5 was negatively correlated with summer mass gain. For lambs and yearlings, winter mass loss was positively correlated with mass on September 15. Our results suggest that at low population density, sheep optimize rather than maximize summer mass accumulation. Most sexual dimorphism develops after weaning, through faster mass gain by males than by females at 1 and 2 years of age and possibly a longer season of mass gain each year for males than for females after females reach puberty.


Author(s):  
Fernando Isaac Gastelum-Mendoza ◽  
Luis Antonio Tarango-Arámbula ◽  
Genaro Olmos-Oropeza ◽  
Jorge Palacio-Núñez ◽  
Diego Valdez-Zamudio ◽  
...  

Objective: To determine the diet of the desert bighorn sheep and to identify differencesin its composition between sexes during the reproductive and sexual segregation periods.Design/methodology/approach: The study was carried in the UMA Rancho NocheBuena, Hermosillo, Sonora. The microhistological technique and a cell catalog of plantsfrom the study area were used to identify plant species present in fecal samples ofbighorn sheep. The relative frequency, the Shannon-Weaver diversity index and theKulczynski similarity index were determined by sex and period (reproductive andsegregation)Results: The diet of bighorn sheep included 40 species, being herbaceous (36.1 ±4.4%) and grasses (26.8 ±8.9 %) the most common. The diet of males during thesegregation period was mainly composed of grasses (36.2%) and female diet byherbaceous (30%) and grasses (29.8%). No differences were found in the diversity ofthe diet of males and females in the segregation period (H '= 1.0) and in general, their diets were very similar (80%).Limitations/implications: To collect a greater number of fecal samples by sex andperiod (reproductive and segregation) and to analyze the nutritional content of plantsconsumed by bighorn sheep.Findings/conclusions: In this study, the sexual segregation exhibited by the bighornsheep in the Wildlife Management and Conservation Unit Rancho Noche Buena was notdue to food preferences.


2018 ◽  
Vol 10 (15) ◽  
pp. 12990-12994
Author(s):  
Suvarna S. Khadakkar ◽  
Ashish D. Tiple ◽  
Arun M. Khurad

Immature stages of Scaptodera rhadamistus (Fabricius) are described for the first time along with notes on nidification and biology.  The larvae differ from other Scarabaeinae species in the structure of raster on tenth sternum with two irregular bunches of serrations ventrally one on either half.  Pupae with pronotum transverse having rounded margins resemble adults, and consist of four lateral, single caudal and single pteronotal support projection.  Adult males and females differ in coloration, structure of pronotum, presence of spine like process on mesosternum and, in the structure of male and female genitalia.


2010 ◽  
Vol 42 (4) ◽  
pp. 476-489 ◽  
Author(s):  
Cody A. Schroeder ◽  
R. Terry Bowyer ◽  
Vernon C. Bleich ◽  
Thomas R. Stephenson

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