Territorial Males Research Articles

MORPHOLOGICAL VARIATION OF THREESPINE STICKLEBACK (GASTEROSTEUS ACULEATUS) ON DIFFERENT STAGES OF SPAWNING PERIOD

This study uses morphometric analysis for better understanding processes occurring during the spawning period in the population of threespine stickleback Gasterosteus aculeatus . Totally, 270 specimens were sampled in 2016 in the Keret Archipelago (White Sea) from three spawning grounds of different quality in the beginning (28–30 May), middle (15–17 June) and end (7–9 July) of spawning period. Nine characters describing fish body shape were measured on each specimen using scanned image and caliper: 1) Total Length, 2) Standard Length, 3) Head Length, 4) Maxilla Length, 5) Distance Between Head and Pectoral Fin, 6) Body Depth, 7) Body Thickness, 8) Head Thickness, 9) Caudal Length. For analyses, we used ratio of characters 3–9 to Standard Length. Principal Component Analysis has separated several groups of characters, describing the upper part of the body (Characters 3–5), body volume (Characters 6–8), and Caudal Length (9). Separation of the groups was similar in both sexes. All groups of characters showed notable changes during the spawning period. In the beginning, the spatial heterogeneity of samples was low, meaning that in wintering locations the population is not structured. In the middle of spawning season, the highest heterogeneity was observed. Males characterized by larger upper part of the body and larger size, were numerous in high quality spawning grounds (characterized by high density of sea grass and stickleback). This probably results from a competition between territorial males for higher quality spawning grounds. In the end of spawning period no spatial heterogeneity was observed, probably, because most of stickleback left the spawning grounds and no competition for higher quality spawning grounds took place. Spatial heterogeneity was somewhat lower in females, but also statistically significant in several cases. Group of characters describing body volume, in general, showed the decline during the spawning period, reflecting release of eggs in females and loss of energy associated with spawning (more pronounced in males guarding their progeny). Superimposition of several processes, such as competition for fish for better spawning grounds, release of eggs and loss of energy associated with spawning, and inshore and offshore migrations, results in a dynamic and complicated picture of morphological heterogeneity occurring during the spawning season of the threespine stickleback.

Does Population Density Determine the Mating Strategy in Males of the Water Strider Aquarius paludum?

Mating behavior of a large Aquarius paludum paludum (Fabricius 1794) (Hemiptera: Gerridae: Gerrini) population was investigated on several field surveys during the mating season. Both types of mating behavior known for semi-aquatic true bugs were observed in the studied population: aggressive Type I mating for non-territorial males and unaggressive Type II mating for the territorial males. Some males establish individual territories at the lake shores that they defend for around one hour and switch to aggressive mating if they fail to attract a female to mate, while most males remain non-territorial. Radial 1–1.5 meter territories were aggressively defended from other males, conflicts being always won by the male already occupying the territory. The presence of Type II males is conditioned by the absence of sufficient space for all males to establish territories. Contact guarding was much longer than documented before for A. paludum paludum, lasting for at least 12–13 hours in some cases. Based on the observations and on the existing information on the group, a more comprehensive classification of mating behavior of true bugs is proposed: Type I - non-territorial, unsignaled grasping, with contact guarding; Type II - territorial, signaled mounting with noncontact guarding; Type III - non-territorial, signaled mounting with contact guarding.

Censusing a tawny owl (Strix aluco) population living at high density merging two consolidated techniques

ABSTRACTThe risk of overestimating the number of nocturnal owls during a census is substantial when the territory density is high and no individual signature is available. The tawny owl voice was demonstrated to be individual, but no statistical technique evaluated to date is suitable for a census of this species. To overcome the problem, the combination of two methods is suggested in this study: (1) the Visual Spectrographic Comparison (VSC), a bioacoustics tool which tries to separate owls’ voices classifying the spectrograms of their calls based on their visual characteristics, and (2) the extensively used technique of Mapping Method (MM). The technique was applied to a dense population of tawny owls living in an isolated deciduous wood of northern Italy. Fourteen territorial males were individuated in the area, resulting a density of 6.0 pairs/km2. Most of the home ranges seem to overlap substantially, an evidence not in step with the common idea of high territoriality of the species. Since the technique is believed to be exhaustive, a future monitoring of this population could be precise, cheap and very informative. This technique could be easily extended to other elusive species that show individual vocal cues.

Monitoring social behaviour as an assessment of translocation success in a reintroduced population of the endangered Leon Springs pupfish (Cyprinodon bovinus)

Abstract Translocation of endangered species from captivity into the wild is a common conservation practice used to bolster populations, expand natural ranges, and restore species that have been extirpated. Often little is known of the fate of organisms after they are released, and extended monitoring of reintroduced populations is necessary for understanding the efficacy of this method. Thought to have become extinct, the endangered Leon Springs pupfish (Cyprinodon bovinus) was rediscovered in 1965. Recently, conservation efforts have focused on renovating their natural habitat and reintroducing C. bovinus from a captive colony established in 1976 back into the ancestral habitat. A reintroduction was performed in 2015, and the population was monitored over the next 14 months to ascertain whether territorial males were behaving typically for the species, and whether there were any changes in social behaviour over time. An established population in nearby Diamond Y Spring was used as a benchmark for typical social behaviour, and as an indicator for any expected seasonal differences in behaviour. The development of a typical social system at Monsanto Deep Pool was evident almost immediately, as males started to establish breeding territories, defend them from intruders, and participate in reproductive activities, such as courtship and spawning. The presence of juveniles within a year indicated that individuals were successfully reproducing. It appears that the translocated C. bovinus are developing into a stable and reproductively successful population.

Are both notes of the common cuckoo’s call necessary for familiarity recognition?

Common cuckoos (Cuculus canorus) are best known for their simple two-note calls (“cu-coo”), which are uttered only by males during the breeding season. A previous playback study revealed that territorial males were more tolerant toward playbacks of the calls of familiar, neighbouring individuals than toward unfamiliar, stranger simulated intruders, exhibiting the classical “dear-enemy” phenomenon. Here we experimentally assessed whether the acoustic cues for familiarity recognition are encoded in the first and/or second note of these simple calls. To do so, we played mixed sound files to radio-tagged cuckoos, where the first part of the two-note calls was taken from strangers and the second part from neighbours, or vice versa. As controls, we used behavioural data from two-note neighbour and two-note stranger call playbacks. Cuckoos responded consistently to the two types of mixed sound files. When either the first or second note of the call was taken from a stranger and the other note from a neighbour, they responded to these sound files similarly to two-note playbacks of strangers: they approached the speaker of the playbacks more closely and the calling response-latency to playbacks was longer than to familiar controls. These findings point to the importance of both notes in familiarity recognition. We conclude that familiarity recognition in male common cuckoos needs the complete structure of the two-note cuckoo call, which is characteristic for this species.

Dung-pile use by guanacos in eastern Patagonia

Abstract Previous studies on guanacos have reported that only territorial males create and maintain dung-piles. The aim of this analysis was to compare dung-pile use by territorial males with the use by females and young in family groups, and by bachelor males. Although territorial males showed the highest dung-pile use, all individuals dropped feces on piles frequently, in contrast to what was previously observed within other guanaco populations. Besides stressing the behavioral plasticity of guanacos, these results suggest an additional adaptive function of localized-defecation other than demarcating territory ownership by the territorial male.

Temporal patterns of extra-pair paternity in a population of Grasshopper Sparrows (Ammodramus savannarum) in Maryland

The incidence of extra-pair paternity (EPP) is highly variable across bird taxa. While EPP is known to affect reproductive variance, the causes of temporal variation in rates of EPP are poorly studied. Breeding density has often been proposed as an important factor influencing EPP variation, but it has received mixed support. Over a 5-year period we examined the rate of EPP in a socially monogamous Grasshopper Sparrow (Ammodramus savannarum) population on a restored grassland in Maryland. Of 124 broods, 62.1% had extra-pair young (EPY), and of 448 nestlings, 36.8% were the result of extra-pair fertilizations. Over the 5-year study, percent EPY ranged from 26% to 60%. EPP rates were positively correlated with the local density of territorial males, supporting the density hypothesis, and 81% of the EPY were from neighboring males. Male within-pair mating success was related to extra-pair mating, suggesting an active behavioral tradeoff between within- and extra-pair matings, especially at high densities. By examining males at the individual level, we found males that were not cuckolded also had the most genetic offspring (within-pair and extra-pair), whereas males that were cuckolded also failed to sire many extra-pair offspring. Here we show that density plays an important role in the availability of mates, EPP, and the opportunity for sexual selection. Received 9 April 2016. Accepted 3 August 2017.

Estimating national population sizes: Methodological challenges and applications illustrated in the common nightingale, a declining songbird in the UK

Abstract Estimation of national population size can be important for setting conservation priorities, but its methodology has received little critical attention. Sites for highly aggregated species are often prioritised if they contain 1% of national or biogeographic populations, but the utility of this approach for other species is unclear. To make recommendations for study design, we present methods used to estimate the UK population size of the common nightingale Luscinia megarhynchos. We assess the sensitivity of the population estimate to the analytical method used and identify sites of national importance for this territorial songbird. Survey effort was directed by prior knowledge of the species distribution and the survey design maximised detectability by focussing on the period of greatest song output. We used three different statistical methods to account for detectability, estimating that 55%–65% of the national population was detected during surveys. Birds in areas not known to contain the species accounted for 13%–23% of the population estimate. Methods to account for these individuals contributed the greatest uncertainty to the results, due to the difficulty of surveying a very large sample of random sites and consequent need to stratify the sample. The 12 derived estimates ranged between 5,094 and 5,938 territorial males, with the confidence limits ranging from 4,764 to 6,534. Site delimitation, using clustering based on nearest‐neighbour distances, identified one site clearly of national importance and several others potentially nationally important, depending on the population threshold and clustering distance used. Synthesis and applications. National population estimation is difficult and requires that species‐specific variability in detectability, and individuals present outside surveyed areas are accurately accounted for through survey design and statistical analysis. Accounting for these sources of error will not always be possible and will hamper efforts to assess true population size and consequently to determine whether sites, however defined, exceed critical thresholds of importance. Resources may be better invested in other activities, for example, in generating population trends based on relative indices. The latter are generally easier to produce, potentially more robust and arguably more suitable for many conservation applications.

Male-male aggression is unlikely to stabilize a poison frog polymorphism.

Phenotypic polymorphism is common in animals, and the maintenance of multiple phenotypes in a population requires forces that act against homogenizing drift and selection. Male-male competition can contribute to the stability of a polymorphism when males compete primarily with males of the same phenotype. In and around a contact zone between red and blue lineages of the poison frog Oophaga pumilio, we used simulated territorial intrusions to test the nonexclusive predictions that males would direct more aggression towards males of (i) their own phenotype and/or (ii) the phenotype that is most common in their population. Males in the monomorphic red and blue populations that flank the contact zone were more aggressive towards simulated intruders that matched the local coloration. However, males in the two polymorphic populations biased aggression towards neither their own colour nor the colour most common in their population. In sympatry, the rarer colour morph gains no advantage via reduced male-male aggression from territorial males in these O.pumilio populations, and so male aggression seems unlikely to stabilize colour polymorphism on its own. More broadly, these results suggest that the potential for divergent male aggression biases to maintain phenotypic diversity depends on the mechanism(s) that generate the biases and the degree to which these mechanisms persist in sympatry.

The spatial dynamics of female choice in an exploded lek generate benefits of aggregation for experienced males

The spatial distribution of prospective mates can dramatically affect the process and outcome of mate choice. In a variety of species, spacing between males influences the likelihood that females visit particular individuals or respond to competing signals. Discrimination by females is expected to be highest among neighbouring males, yet males of some species aggregate in ways that apparently facilitate such comparisons. To better understand the selective pressures affecting male aggregation, we investigated how spatial organization of male territories related to female mate sampling tactics and male mating success in the lance-tailed manakin, Chiroxiphia lanceolata. This species displays in a dispersed lek of alpha males, each of which usually has a subordinate beta partner that participates in displays but does not mate with females attracted by their cooperative courtship. We video-recorded courtship activity at display perches of 12 alpha–beta pairs for 42 days in 2013, and documented 478 visits by 82 banded females. We further quantified the relationship of aggregation with genetic mating success for 49 alphas displaying at georeferenced locations in 5 years. Males with close neighbouring alphas were visited by more females, but geographic centrality was unrelated to female visit frequency. Females moved shorter distances between consecutive courtship visits than expected at random, but only 20.5% of 73 females visiting males with video-monitored nearest neighbours visited both neighbouring alpha males. Effects of aggregation on annual genetic reproductive success were only evident after accounting for the stronger effects of alpha age and experience, and only experienced alphas benefited from having close neighbours. Selection for aggregation more likely influences social behaviour of older alphas than settlement decisions by younger males. Benefits of aggregation for experienced alphas mitigate declines in old age, and may generate selective pressure favouring the long-term social alliances that are a key characteristic of this mating system.

Multiple signaling in a variable environment: expression of song and color traits as a function of ambient sound and light

AbstractMany animals communicate using more than one signal, and several hypotheses exist to explain the evolution of multiple signals. However, these hypotheses typically assume static selection pressures, and previous work has not addressed how spatial and temporal environmental variation can shape variation in signaling systems. In particular, environmental variability, such as ambient lighting or noise, may affect efficacy (e.g., detectability/perception by receivers) of signals. To examine how signal expression varies intraspecifically as a function of habitat characteristics, we evaluated relationships between spatial environmental variation and song and plumage color expression in a tropical songbird, the Red‐throated Ant‐tanager (Habia fuscicauda) in Panama. We recorded male ant‐tanager song, plucked feathers to measure coloration, and quantified the acoustic and light environments from each male's territory. In addition, we took several morphological measurements from each male to assess the potential information content of song and plumage color. We found that males with redder and more saturated crown plumage occurred on darker territories, and males that sang shorter and lower frequency songs occurred on noisier territories. We also found that more colorful males tended to sing longer and lower frequency songs. Finally, we found that song and color correlated similarly with male morphology (e.g., tarsus length, body mass). Altogether, these results indicate that spatial variation in the environment is related to male coloration and song, and that males might be optimizing color and song expression for their particular territorial environment.

Courtship behaviour and display-site sharing appears conditional on body size in a lekking bat

Leks are aggregations of sexually displaying males visited by receptive females and characterized by intense male–male competition to attract mates. Success in lekking species is often contingent upon male display output and/or lek attendance, with energetically costly displays functioning as an honest indicator of male quality. Furthermore, display spaces are vigorously defended by territorial males, and territory characteristics are often linked to male phenotype. Here we describe the courtship and territorial behaviour of lekking lesser short-tailed bats, Mystacina tuberculata, and both behaviours appear to be conditional on body size. During the breeding season, lekking males occupy and defend small tree hollows and sing for long periods of the night to attract females. Although some males sing alone, others form ‘timeshare’ singing roosts, where multiple males visit sequentially to sing each night. In our study, solitary males were significantly smaller than timeshare males and individually had both higher song outputs and higher roost occupancy rates, although timeshare roosts had higher overall occupancy rates. There appeared to be no fitness difference between the two male groups, and while one timeshare roost contained relatively closely related individuals (which roost settlement simulations indicate was not a chance event), four did not. We discuss factors that may promote timeshare formation, including competition for access to desired roosts and potential by-product mutualisms. Courtship and sexual selection in bats is largely undescribed, and thus our study provides a useful description of behaviour in a little-studied taxon.

Seminal fluid enhances competitiveness of territorial males' sperm in a fish with alternative male reproductive tactics.

The most common adaptation to sperm competition in males is represented by an increase in the sperm number and/or quality released at mating, to raise their probability of egg fertilization. However, rapidly mounting evidence highlights that seminal fluid may directly influence the competitive fertilization success of a male by affecting either own and/or rival sperm performance. In the black goby, Gobius niger, an external fertilizer with guard-sneaker mating tactics and high sperm competition level, sneaker ejaculates contain less seminal fluid and more sperm, that are also of better quality, than those of territorial males. However, territorial males gain a higher paternity success inside natural nests. Here, we ask whether the seminal fluid can contribute to the reproductive success of territorial males by enhancing their sperm performance and/or by decreasing that of sneaker males. Using sperm and seminal fluid manipulation and in vitro fertilization tests, we found that own seminal fluid influences the velocity and fertilization ability of sperm only in territorial males, making them as fast as those of sneakers and with a similar fertilization rate. Moreover, both sneaker and territorial sperm remain unaffected by the seminal fluid of rival males. Thus, black goby males respond to the different level of sperm competition faced by differential allocation of sperm and non-sperm components of the ejaculate, with sneakers primarily investing in sperm of intrinsic high quality and territorial males relying on the effect of seminal fluid to increase the lower intrinsic quality of their sperm.

Effect of territory intruders on the perceived quality of territorial males in an endangered pupfish, Cyprinodon bovinus

Abstract Social eavesdropping can guide mate choice and the assessment of competitor quality. In the endangered Leon Springs pupfish (Cyprinodon bovinus), males establish breeding territories that they defend from conspecifics and heterospecific egg predators. Females enter the breeding area to assess males and spawn in their territories. It was hypothesized that male and female C. bovinus eavesdrop on social interactions within male territories to evaluate each territorial male’s ability to exclude intruders and attract potential mates. Using a repeated design, a bottle containing either a female C. bovinus, a non-territorial male C. bovinus, a swarm of G. nobilis, or water was placed at the centre of a male’s territory. Territorial males received more spawns and females spawned more frequently per visit when a female stimulus was present. These results suggest that females eavesdrop to inform their mating decisions, but this may be limited to the assessment of extra-pair females within territories.

Patterns and correlates of within-season breeding dispersal: A common strategy in a declining grassland songbird

ABSTRACT Dispersal is a ubiquitous behavior with important consequences for gene flow, demography, and conservation. Some birds engage in between-year breeding dispersal, but the factors shaping variation in this behavior are not well understood. In mid-continental grasslands, preliminary evidence suggested that Grasshopper Sparrows (Ammodramus savannarum) dispersed not only between seasons, but also within breeding seasons—an apparently uncommon avian behavior. We studied a population of Grasshopper Sparrows breeding in northeastern Kansas, USA, to document the spatial and temporal patterns of within-season breeding dispersal in an experimentally managed tallgrass prairie from 2013 to 2015. We combined color-band resighting, territory mapping, and radio telemetry to quantify changes in territory density, turnover of territorial males, and dispersal distances. Density of Grasshopper Sparrows varied seasonally in management-specific ways, simultaneously increasing and decreasing in watersheds that differed...

Fight, fatigue and flight: narrowing of attention to a threat compensates for decreased anti-predator vigilance.

Fighting carries a predation risk because animals have limited attention, constraining their ability to simultaneously engage in aggression and anti-predator vigilance. However, the influence of interspecific aggression and fatigue on the predation cost of fighting is seldom examined, although both are unignorable aspects of fighting. Here, I incorporated both factors in a series of field experiments on the cichlid Lamprologus ocellatus. If territorial males respond more strongly to conspecific territorial intruders than to heterospecific intruders, then they should delay escape more frequently during intraspecific fighting than during interspecific fighting. Consequently, although I predicted that vigilance would be decreased as fighting progresses in both cases, intraspecific aggression should decrease vigilance more than interspecific aggression. Males were also exposed to a predator approaching at different (slow or fast) speeds during these fighting bouts. Delays in predator detection and flight initiation were quantified and these predictions were tested. As predicted, males responded more strongly to intraspecific intruders, resulting in slower predator detection and fleeing times than when encountering interspecific intruders. Furthermore, flight latency decreased with increasing fight duration, suggesting that fatigue negatively influenced escape responses. However, contrary to the prediction, the vigilance decrement rate was faster in response to slow predators than in response to rapid predators, and was not influenced by intruder identity. This suggests that fighting males reserve their attention for information critical to their survival and are less vigilant toward a less-threatening (slowly approaching) predator. This cognitive allocation may be an adaptive compensation for fatigue-related low vigilance during fighting.

Survival of adult Steller sea lions in Alaska: senescence, annual variation and covariation with male reproductive success.

Population dynamics of long-lived vertebrates depend critically on adult survival, yet factors affecting survival and covariation between survival and other vital rates in adults remain poorly examined for many taxonomic groups of long-lived mammals (e.g. actuarial senescence has been examined for only 9 of 34 extant pinniped species using longitudinal data). We used mark–recapture models and data from 2795 Steller sea lion (Eumetopias jubatus) pups individually marked at four of five rookeries in southeastern Alaska (SEAK) and resighted for 21 years to examine senescence, annual variability and covariation among life-history traits in this long-lived, sexually dimorphic pinniped. Sexes differed in age of onset (approx. 16–17 and approx. 8–9 years for females and males, respectively), but not rate (−0.047 and −0.046/year of age for females and males) of senescence. Survival of adult males from northern SEAK had greatest annual variability (approx. ±0.30 among years), whereas survival of adult females ranged approximately ±0.10 annually. Positive covariation between male survival and reproductive success was observed. Survival of territorial males was 0.20 higher than that of non-territorial males, resulting in the majority of males alive at oldest ages being territorial.

Territorial behaviour of male roe deer: a telemetry study of spatial behaviour and activity levels

The roe deer (Capreolus capreolus) is considered a special case of territorial ungulate. This study aimed to contribute to the knowledge of male roe deer territoriality by exploring its spatial use and activity patterns. We divided the territorial period (March–August) into three two-month sampling periods and found that the home range (HR) size of 13 radio-collared males averaged from 47.9 ± 14.5 ha to 109.7 ± 31.9 ha. We classified the spatial behaviour of eight out of the 13 males into three groups and concluded that HR size variation alone did not explain the potential territorial status. Nevertheless, it was indicative of their territorial status when considered along with the bucks’ age, spatial movements and activity levels. The activity levels of July–August were significantly lower than the activity levels of March–April. HR size variation of the males monitored significantly contributed to explain the variations in their activity levels. Old bucks were significantly less active than other males, especially during July–August. To sum up, we found an indication of an influence of spatial profiles on activity levels, though a larger sample will be needed in order to better understand differences in age and territorial status, and inter-individual differences in activity.

The importance of willow to the Chinese Grouse: evidence from analysis on their breeding territories at Lianhuashan, China

BackgroundThe habitat features of breeding territory have important adaptive significance for the survival and reproduction of territory holders. The Chinese Grouse (Tetrastes sewerzowi) is a rare and endemic species with relatively small distribution range and decreasing population trend. It is important to elucidate breeding territory habitat requirements of the Chinese Grouse for habitat management and conservation actions.MethodsUsing radio-telemetry and field observations, we determined the core areas of 65 breeding territories of males. Two to three samples were selected in each core breeding territory as used sites and compared with nearby sites with no grouse occurrence using logistic regression.ResultsOur model showed a high accuracy in prediction of core breeding territory used by males, which preferred stands with more small deciduous trees (0.5 m ≤ height < 5 m), more small willow trees (Salix spp., 0.5 m ≤ height < 5 m), greater willow cover, and greater herb cover. The number of small willow trees had the greatest influence on males’ core breeding territory selection. Dense shrubs were also chosen compared with unused sites. Tall conifer trees was an important determinant in the distribution of Chinese Grouse at the landscape scale, and was relatively important in the univariate model, but not included in our final multivariable model.ConclusionsMale Chinese Grouse established territories at sites with abundant food resources. At the landscape scale, the Chinese Grouse occurred in alpine conifer forest. At the territory scale, small willow trees had the most important effect on males’ core breeding territory selection. We suggest that the forest gaps in dense conifer forest are important for improving the occurrence of willows and facilitating breeding territory establishment for the Chinese Grouse.

La presencia invisible de la mujer deportista en la prensa deportiva española. Análisis de las portadas de "Marca", "As", "Mundo Deportivo" y "Sport" (2010-2015

La realidad de las mujeres sigue siendo explicada por los medios de comunicación desde una perspectiva androcéntrica, a pesar de una mayor presencia femenina en la esfera pública. En el contexto del periodismo deportivo, la cobertura mediática de las deportistas es discreta, incluso nula. Cualitativamente, la información referida a las mujeres y a su actividad recurre de manera reiterada a los estereotipos de género. Ello se debe a que, tanto el deporte en sí como el periodismo deportivo, se han construido como un territorio predominantemente masculino, donde las desigualdades de género y los prejuicios sexistas se han legitimado. La presente investigación analiza las portadas de los cuatro diarios deportivos más leídos en España (Marca, As, Mundo Deportivo y Sport) durante un periodo de cinco años (2010-2015), los resultados de la cual reafirman que “el deporte continúa existiendo por, para y sobre los hombres” (Cooky et al., 2013: 205)