Counts of greater sage-grouse (Centrocercus urophasianus) at leks have been used in harvest management, Endangered Species Act listing decisions, and land management policies for over half a century. ...Lek count sampling methods focus on counting male sage-grouse at known leks, primarily those observed visually from roads or vantage points, but leks are likely missed that are unknown prior to the survey and are difficult to detect while driving between known lek sites. One way to ameliorate this shortfall may be to conduct short point-count surveys at multiple stops along lek-survey routes or while driving between lek counts, thereby detecting newly established or unknown leks. To evaluate the feasibility of this approach, we estimated aural and visual detection probability of active sage-grouse leks during 1-minute point-count surveys at known distances and examined the effects of environmental factors on aural lek detection in southern Idaho, USA, 2016–2017. Our results demonstrate that field observers can aurally detect sage-grouse leks at approximately 3 times greater distances compared to detecting leks visually. The probability of hearing an active lek was highest near the peak of male and female attendance (8 Apr), within an hour of sunrise, on relatively calm and cold days, when the observer was at a higher elevation relative to the lek, and during conditions with no background noise. Detection probability declined with distance and the probability of aural detection was 0.59 at 1 km from a lek when other variables were held at their means. Hence, conducting ≥3 1-minute surveys along a lek route would be expected to detect ≥93% of all leks within 1.5 km of each survey under the average environmental conditions in our study. Our results suggest that surveys could greatly improve detection of unknown or newly established leks and can facilitate a more accurate assessment of sage-grouse population trends through lek counts. Moreover, our results demonstrate how environmental factors influence the detection of leks during surveys, and therefore which variables should be considered for inclusion in any future revisions of lek count protocols or in analyses of lek count data.
Sexual selection theory maintains that traits under selection honestly advertise qualities of signaling individuals and that only individuals in the best condition can survive while displaying ...maximally elaborated secondary sexual ornaments. Recent trends in mate choice studies have favored the consideration of the effects of multiple traits on mating success, including suites of traits transmitted in different sensory modalities. Sexual selection is expected to be especially strong in lek-mating species. The lesser prairie-chicken (Tympanuchus pallidicinctus) is a grouse species which breeds on leks. Males of this species perform audio and locomotor displays and exhibit two pairs of brightly colored ornaments. We performed an observational study of mate choice in spring 2016–2018 and noted 40 copulations on seven leks. We quantified behavioral, territorial, and morphological characteristics of males along with ornament color properties. We found that variables from all categories considered predicted female choice. Age had the strongest effect, with adult males experiencing higher female choice relative to yearlings. Allocation of aggressive behavior and comb color properties were also strongly correlated with female choice. Our results show that modulating behavior depending on whether females are present contributes to male mating success and highlight the importance of the size and color properties of secondary ornaments. Further research is required to determine how the variables most strongly associated with mate choice relate to one another and which aspects of individual quality, if any, are signaled by color ornaments. Future studies could also incorporate variables related to females to determine if selection on females occurs.
The evolution of female preference for male genetic quality remains a controversial topic in sexual selection research. One wellknown problem, known as the lek paradox, lies in understanding how ...variation in genetic quality is maintained in spite of natural selection and sexual selection against low-quality alleles. Here, we theoretically investigate a scenario where females pay a direct fitness cost to avoid males carrying an autosomal segregation distorter. We show that preference evolution is greatly facilitated under such circumstances. Because the distorter is transmitted in a non-Mendelian fashion, it can be maintained in the population despite directional sexual selection. The preference helps females avoid fitness costs associated with the distorter. Interestingly, we find that preference evolution is limited if the choice allele induces a very strong preference or if distortion is very strong. Moreover, the preference can only persist in the presence of a signal that reliably indicates a male’s distorter genotype. Hence, even in a system where the lek paradox does not play a major role, costly preferences can only spread under specific circumstances. We discuss the importance of distorter systems for the evolution of costly female choice and potential implications for the use of artificial distorters in pest control.
Fra en casestudie (Becher & Håøy, 2022) henter vi data og utforsker jenter og gutters vennskap og sosiale inkludering ved skolestart. Det empiriske hovedgrunnlaget er fokusgruppe-intervjuer med ...elever, foreldre og lærere i tillegg til barnas egne bilder. Mulighetene for å finne venner og delta i aktiviteter ser ut til å være noe ulike for jenter og gutter. De fleste guttene er opptatt av fotball, mens jentene engasjerer seg i andre aktiviteter. Det er krevende å finne nye lekekamerater i en stor, ny og ukjent barnegruppe, og både jenter og gutter kan oppleve utenforskap. Studien bekrefter at det kan være lettere for barn å etablere gode sosiale relasjoner, oppleve tilhørighet til fellesskap og føle seg inkludert når de begynner på skolen sammen med kjente barn. Men, vi finner at barna trenger støtte fra lærere for å opprettholde disse relasjonene. Videre finner vi at prestasjoner og ferdigheter vektlegges fra skolestart, noe som kan svekke fokus på sosial inkludering, kontinuitet og trygghet. English abstract Girls’ and Boys’ Friendships and Social Inclusion at the Start of School From a case study (Becher & Håøy, 2022) we use data as we explore girls’ and boys’ friendships and social inclusion at the start of school. The main basis for data is focus group interviews with students, parents, and teachers as well as children’s photos. The possibilities for finding friends are somewhat different for girls and boys. Most of the boys are playing football, while the girls engage in other activities. It is challenging to find new playmates in a large, new, and unknown community of children, and both girls and boys can experience exclusion. The study confirms that it may be easier for children to establish positive social relationships, get a sense of belonging to community and feel included when they start school with children they already know. However, we find that children need support from teachers to maintain established relationships. Furthermore, we find that there is a strong focus on performance and skills from the beginning. This can weaken the emphasis on social inclusion, continuity and belonging at the start of school.
Many lekking systems exhibit highly skewed male reproductive success, but traits preferred by females are not always evident. In the lance-tailed manakin, Chiroxiphia lanceolata, male reproductive ...success is correlated with age, experience and heterozygosity, but mechanisms by which females might detect these qualities are unknown. Avian chemical signals, such as volatile compounds present in preen oil secreted by the uropygial gland, have been shown to predict reproductive success, correlate with genetic diversity and indicate body condition and immune function in temperate passerines. Here we tested whether preen oil volatile compounds contain information about individual characteristics related to mate choice in male and female lance-tailed manakins, including social and breeding status, heterozygosity and age. In males, preen oil volatile profiles reflected heterozygosity but not social status or age. In females, we found a relationship between volatile profiles and age but not breeding status or heterozygosity. Volatile compounds covaried with sampling date in both sexes. The information reflected in manakin volatile profiles suggests that they have the potential to serve as mate assessment cues in this species.
•We tested whether chemical profiles reflected traits of lance-tailed manakins.•Male preen oil profiles correlated with heterozygosity, a target of mate choice.•Volatiles were unrelated to male age or social status.•Volatile compounds changed with sampling date in both sexes.•Females may assess male genetic diversity through chemical profiles.
Sex ratio, and the extent to which it varies over time, is an important factor in the demography, management, and conservation of wildlife populations. Greater sage‐grouse Centrocercus urophasianus ...populations in western North America are monitored using counts of males at leks in spring. Population estimates derived from lek‐count data typically assume a constant, female‐biased sex ratio, yet few rigorous, empirically derived estimates of sex ratio are available to test that assumption. We estimated pre‐breeding sex ratio of greater sage‐grouse in a peripheral, geographically isolated population in northwestern Colorado during two consecutive winters using closed‐population, robust‐design, multi‐state, genetic mark–recapture models in program MARK. Sex ratio varied markedly between years, with estimates of 3.29 (95% CI: 2.36–4.59) females per male in winter 2012–2013 and 1.54 (95% CI: 1.22–1.95) females per male in winter 2013–2014. Rather than assuming a constant sex ratio, biologists should consider the potential for large annual variation in sex ratio of greater sage‐grouse populations when estimating population size or trend from male lek‐count data.
A fundamental issue in cetacean conservation is determining the occurrence, distribution, and habitat use of target species. However, these baselines are extremely deficient in many poorly ...investigated regions, making it challenging to inform conservation management initiatives. In this case study, we employed three complementary approaches to generate conservation baselines on a “Vulnerable” near-shore delphinid species, the Indo-Pacific humpback dolphin, Sousa chinensis, in the waters southwest of Hainan (SW Hainan), China. First, in late 2013, we conducted large-scale local ecological knowledge (LEK) surveys with 510 Hainanese fishers. Our LEK findings revealed that SW Hainan was a previously underreported area with numerous fishermen encounters of humpback dolphins dating back to the 1970s. Second, from 2014 to 2019, we conducted monthly boat-based visual surveys in SW Hainan. Our sighting data verified the reliability of previous LEK findings and further confirmed the year-round occurrence and species dominance of humpback dolphins in SW Hainan. Third, we applied a supplementary approach (stationary passive acoustic monitoring, PAM) to monitor dolphin biosonar activities in the region. Our 10-site PAM dataset from February 2018 to June 2019 indicated spatiotemporal variations in dolphin click detections. To conclude, our findings, derived from multiple approaches, provide a scientific basis for cetacean conservation management and marine spatial planning on a regional scale. More generally, this study offers an integrated monitoring strategy consisting of three step-by-step approaches, which can help conservationists, especially those who work in data-deficient waters, obtain critical baseline data on cetaceans in an efficient, timely, and reliable way.
•Many methods can be applied to provide conservation-valuable insights into cetacean ecology, while each has its own pros and cons.•Three approaches were integrated into a step-by-step monitoring strategy for cetacean conservation research in data-poor regions.•This integrated strategy can offer a comprehensive understanding of cetacean occurrence, distribution, and habitat use patterns.
Competition between the economic and natural assets of forests is emphasised in capercaillie lekking sites, which are often located within production forests. In this study, we assessed the potential ...use of carbon offsets as income for the management of capercaillie lekking sites. We ran simulations and optimisations for two alternative forest management scenarios in ten forest holdings located in five different regions of Finland. The size of each forest holding was approximately 30 hectares, of which 5 hectares was included in a lekking site. The basic scenario followed forest management recommendations, and the carbon sequestration scenario aimed to enhance biodiversity maintenance in a way that enabled carbon offsets to be obtained for the lekking site. We found that the decrease in revenue from timber sales was generally so small that the income from carbon offsets provided an economically better choice. Furthermore, the cost-effectiveness of carbon sequestration did not seem to be restricted to a specific location. The approach we introduced can be utilised in future decision making in the forestry sector to promote the coordination of nature management and forestry. Moreover, carbon pools should be considered more comprehensively in future research.
The biology and ecology of Africa's largest fruit bat remains largely understudied and enigmatic despite at least two highly unusual attributes. The acoustic lek mating behavior of the hammer-headed ...bat (Hypsignathus monstrosus) in the Congo basin was first described in the 1970s. More recently molecular testing implicated this species and other African bats as potential reservoir hosts for Ebola virus and it was one of only two fruit bat species epidemiologically linked to the 2008 Luebo, Democratic Republic of Congo, Ebola outbreak. Here we share findings from the first pilot study of hammer-headed bat movement using GPS tracking and accelerometry units and a small preceding radio-tracking trial at an apparent lekking site. The radio-tracking revealed adult males had high rates of nightly visitation to the site compared to females (only one visit) and that two of six females day-roosted ~100 m west of Libonga, the nearest village that is ~1.6 km southwest. Four months later, in mid-April 2018, five individual bats, comprised of four males and one female, were tracked from two to 306 days, collecting from 67 to 1022 GPS locations. As measured by mean distance to the site and proportion of nightly GPS locations within 1 km of the site (percent visitation), the males were much more closely associated with the site (mean distance 1.4 km; 51% visitation), than the female (mean 5.5 km; 2.2% visitation). Despite the small sample size, our tracking evidence supports our original characterization of the site as a lek, and the lek itself is much more central to male than female movement. Moreover, our pilot demonstrates the technical feasibility of executing future studies on hammer-headed bats that will help fill problematic knowledge gaps about zoonotic spillover risks and the conservation needs of fruit bats across the continent.
A growing body of research suggests that songs are an important part of the courtship behavior of many bat species, however there is little information on the basic characteristics of these ...vocalizations, or how they may function as a courtship signal. Lekking male lesser short-tailed bats (Mystacina tuberculata) appear to use vocal displays as a primary method for attracting mates, but it is unclear if these vocalizations constitute songs, and what characteristics females may use for mate selection. We recorded 16 lekking males and described the frequency and temporal properties of their vocalizations. We identified four notes (upsweeps, downsweeps, trills, and tones) that comprise courtship vocalizations, and males produced these notes either singly, or combined them linearly to form composite syllables. We classified 51 distinct syllable types (with an average of 29 types per male), with four (trills, upsweep-trills, trill-downsweeps, and upsweep-trill-downsweeps) comprising 69% of all syllables produced. The duration of trill-downsweeps scaled negatively with forearm length (a proxy for body size in bats), and all four main syllable types showed evidence of individuality. Based on the behavioral characteristics and contexts of these courtship vocalizations, we posit that this behavior constitutes singing. Furthermore, M. tuberculata potentially has one of the highest sustained song outputs yet described. Our results suggest the singing displays of M. tuberculata are signals that provide useful, honest cues of male characteristics and identity to females, and are as complex as the songs of many passerines.
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