Patterns of mating among male patas monkeys (Erythrocebus patas) in Kenya

An habituated group of wild patas monkeys was observed in Kenya for 550 h in 1984. Observations were made primarily during an interval that, as previous studies at the same site had demonstrated, coincided with the annual mating and conception periods. Earlier field studies of patas at other sites had reported that heterosexual patas groups had only a single resident adult male and that mating was harem-polygynous. At the Kenya site, by contrast, as many as six males were simultaneously resident and mated in the group during the conception period. Males adopted a variety of tactics to gain access to receptive females, ranging from opportunistic mating to attempts at sequestration that resembled consort behavior in other cercopithecoids such as savanna baboons and rhesus macaques. Aggressive competition for access to females took place among the males, although the number of completed copulations per male did not bear a positive relation to agonistic dominance rank. For patas monkeys, harem polygyny is only one available option within an overall mating system that is best described as a form of promiscuous polygyny, especially during periods when conception is most likely.     

Mating system structure and population density in a polygynous lizard, Sauromalus obesus (= ater)

Increases in population density often are associated with achange in mating system structure in numerous taxa. Typically,male interactions are minimal in extremely low density populations.As density increases, males exhibit territoriality but if densitybecomes too high, the energetic cost of defending a territorywill eventually outweigh the reproductive benefits associatedwith territoriality. Consequently, males in high density populationsmay abandon territoriality and adopt dominance polygyny, lekking behavior, or scramble competition. We investigated the relationshipbetween population density and mating system structure in threepopulations of the chuckwalla, Sauromalus obesus (= ater),near Phoenix, Arizona. Densities in the Phoenix Mountains (2.7chuckwallas/ha) were lower than any population previously studied.In the Santan Mountains (10.9 chuckwallas/ha), densities weresimilar to populations studied in the Mojave Desert, and inthe South Mountains (65 chuckwallas/ha), densities were the highest yet recorded. Male mating behavior was examined by determininghome range overlap and by making direct behavioral observations.Male home range size decreased with increasing population density.There was little overlap in home ranges among males in allthree populations, whereas home ranges of males and femalesconsistently overlapped, indicating that males were strictly territorial. This conclusion was supported by behavioral observationsof interactions among individuals in a natural setting. Thenumber of females wihin male territories was correlated withfood resources (plants) in all three populations. Female homerange size appeard to be related to food resources whereasmale home ranges appeared to be related to female distribution,population density, and geology. The retention of territoriality in spite of high population densities raises new questions aboutthe relationship between density and resource defense.     

Spawning behavior and haremic mating system in the corallivorous butterflyfish,Chaetodon trifascialis, at Kuroshima Island, Okinawa

Territorial and spawning behavior ofChaetodon trifascialis were investigated on a small patch of reef at Kuroshima Island, Okinawa, Japan. Three males and 8 females inhabited the reef, each individual defending a territory against conspecifics of the same sex. Each male territory included 2 or 3 female territories. In the daytime, each male frequently visited the females living in its territory. At dusk in the full or new moon periods, courtship began within the female territories, pair spawning subsequently occurring within or near those territories. When a male actively courted a female in the territory of a second male, the latter male immediately chased off the intruder. Thus, mating occurred only between a male and females living in former's territory. This is the first report of a haremic mating system among butterflyfishes (Chaetodontidae).     

The mating system of a bee fly (Diptera: Bombyliidae). II. Factors affecting male territorial and mating success

Males of an undescribed bombyliidfly (Comptosia sp.)occupy traditional territories on a Southeast Queensland hilltop, to which females come solely for the purpose of mating. Territorial fights between males involve aerial collisions during which modified spines on the wing margins produce scars on the bodies of opponents. Territory owners and mating males are not different in size or age from the remainder of the male population. Although residency is related to fighting success, the strength of the effect is ambiguous. Consequently, our data do not appear to fit predictions from game theoretical models for fighting protocol. Hilltop males lacked the extensive population variation typically found in territorial species, and thus, the presumed advantages of traits such as large size may be suppressed. Hilltop males were larger than males at a nonhilltop, resource-based mating site and the possibility of alternative mating tactics is discussed.     

The effects of male body size on territorial and mating success in the landmark-defending fly Hermetia comstocki (Stratiomyidae)

Abstract.

• 1 Males of Hermetia comstocki Williston compete for territorial control of certain agaves and yuccas. Winners copulate with females that visit these plants solely to acquire a mate.
• 2 Males vary in body weight by more than an order of magnitude and larger flies almost always defeat smaller ones in aerial contests for control of landmark territories.
• 3 The mean body size (as measured by wing-length) was significantly greater for males retaining residency at a site for at least one hour compared to males unable to do so. Likewise, males able to return to a perch site in the study area on more than one day were larger on average than males unable to do so.
• 4 Male preferences for landmark territories remained similar across years. Large males dominated the perch landmarks most likely to be occupied by males and most likely to be visited by females.
• 5 Despite the fighting and territorial advantages enjoyed by large males, the mean size of males found mating with females was not significantly larger than that of the general population.
• 6 The apparent failure of large males to secure a statistically significant mating advantage may be a statistical consequence of the small sample size of males observed mating. On the other hand, any mating advantage of large males may be reduced because (a) receptive females visit many different landmarks, (b) females mate with the first male they encounter at a landmark, regardless of his size, (c) there are usually many vacant landmarks available for smaller males, and (d) even popular territories are often open to small males, thanks to the low site-tenacity of territory owners.

     

Spatial behaviour in the Aquatic Warbler (Acrocephalus paludicola) during mating and breeding

Summary The range use of both sexes of the Aquatic Warbler was studied during two breeding seasons by radio-tracking. Males used home ranges of up to 8 ha. These home ranges over-lapped by up to 74 %, (mean 51 %) between individuals. During the mating period and prior to nesting, females used isolated sites of 2.8 to 6.4 ha (mean: 4.2 ha) within activity ranges of 100 to 160 ha (mean: 120 ha). Home ranges of different females overlapped by up to 20 %. However, during nest-building and incubation, the average size of home ranges in females was only 1.6 ha. Since no constant ranges were observed, we conclude that Aquatic Warblers are not territorial in the breeding season.

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Räumliches Verhalten des Seggenrohrsängers (Acrocephalus paludicola) während Partnerfindung und Bebrütung

Zusammenfassung In zwei aufeinanderfolgenden Brutzeiten wurde die Raumnutzung von Seggenrohrsängern mittels Telemetrie untersucht. Die ermittelte Größe der Streifgebiete von Männchen betrug in der gesamten Brutzeit bis zu 8 ha. In dem Streifgebiet eines einzelnen Männchens wurden bis zu elf telemetrierte Männchen festgestellt. Die Überlappungen der Streifgebiete telemetrierter Männchen betrugen durchschnittlich 51 %, maximal 74 %. Weibchen nutzten während der Paarungszeit nicht zusammenhängende inselartige Areale von insgesamt 2,8 bis 6,4 ha (Mittelwert 4,2 ha) innerhalb von Aktionsräumen von 110 bis 160 ha (Mittelwert 120 ha). Diese Areale überlappten zu 20 % mit den Aufenthaltsgebieten anderer Weibchen. Während des Brütens sank die Größe der Streifgebiete der Weibchen auf durchschnittlich 1,6 ha. Da im Beobachtungszeitraum keine konstant genutzten Aufenthaltsgebiete vorlagen, schließen wir, daß sich Seggenrohrsänger in der Brutzeit nicht territorial verhalten.

     

Sexual dimorphism,mating system,and effect of phylogeny in De Brazza's monkey (Cercopithecus neglectus)

De Brazza's monkey (Cercopithecus neglectus), like other guenons, shows marked sexual dimorphism in an array of features. While strong sexual dimorphism is generally associated with a polygynous mating system, populations of De Brazza's monkeys in Gabon are reportedly monogamous. An explanation of this unique phenomenon is offered here. Patterns of sexual dimorphism are examined for morphology, growth and development, behavior, and ecology, and field and captive studies on the social organization and mating system of De Brazza's monkey and congeneric guenon species are reviewed. Based on the findings, it is postulated that 1) De Brazza's monkeys are not strictly monogamous, but exhibit interpopulational variation in their mating system, from facultative monogamy to mild polygyny; 2) marked sexual dimorphism most likely reflects the effect of the historical-phylogenetic factor; ie, it represents a holdover of a degree of dimorphism established earlier in evolutionary history when the degree of polygyny Was higher; and 3) lessening in the degree of polygyny and a tendency toward monogamy represents a consequence of selection toward small group size. Small group size, a unique antipredator strategy, and failure to form polyspecific associations are ultimately most likely the result of intragroup and interspecific competition and predation pressure.     

Male perch selection and the mating system of the robber fly,Promachus albifacies (Diptera: Asilidae)

We studied the activity and spatial distribution of the robber fly,Promachus albifacies, in a desert grassland habitat in central New Mexico. Late in the season males spent most of the daytime on or near cholla and yucca plants that had dead stems or dead flower stalks at least 1 m high. Of the three hypotheses (thermoregulation, foraging, mate encounter site) considered as explanations for this distribution, the mate-encounter-site hypothesis was best supported. Plants used by females as oviposition sites were the focus of male activity. Males perched within or near these plants and attempted copulations with females detected nearby. Most matings were initiated at these locations. Seasonal changes in male and female activity also supported the mate-encounter-site hypothesis. Early in the season, females spent little time ovipositing, and predictably, males spent little time on or near these plants. Such a mating system may be described as resource defense polygyny, since males acted aggressively toward one another at oviposition sites even when females were not present. However, the short tenure of males at these sites is suggestive of scramble competition polygyny. We discuss possible reasons why this particular mating system has evolved.     

The mating system and male mating success of the Virginia opossum (Didelphis virginiana) in Florida

The mating system of the Virginia opossum, a solitary, nocturnal marsupial, was studied over a period of two years in north–central Florida. There were two mating seasons each year, both lasting about four weeks and starting in mid-January and late April, respectively. Radio-tracking males and females revealed that, independent of body size, males doubled their home ranges during these periods to include an average of 5.9 females within their new ranges. Females were visited regularly and, on the night of oestrus, males directly competed for access to the female. Dominance and hence mating success was strongly related to body mass but not age. Dominant males weighed on average 3.18 kg (N = 20) compared to 2.65 kg of unsuccessful males. The largest of the competing males was successful in 20 of 23 cases involving at least two competitors. Individual male mating success varied from zero to three matings during a breeding season, but the range was probably underestimated. Mate searching activities were costly, as most males lost weight during both mating seasons. Weight changes were a function of body mass, with males over 2.2 kg losing up to 23% in weight and smaller males gaining weight. There was also evidence that male breeding activities entailed a survival cost.     

Influences on variation in territorial tenures of male white-faced dragonflies (Leucorrhinia intacta) (Odonata: Libellulidae)

Some individuals in species with extended periods of territorial occupancy may change territory locations within a single bout of territorial activity. Length of occupancy of mating territories among males in a local population of white-faced dragonflies (Leucorrhinia intacta) varied from more than 6 h to 15 min or less. Males with short tenures often established territories in several locations on the pond during a day. Several hypotheses have been proposed to explain shifting territorial sites rather than remaining in a single site during one bout of territoriality. We attempted to test the hypothesis that males shift to leave low-quality sites. Site quality may be affected by costs of defense in relation to intruder rate and the mating benefits of holding the territory. To test whether variation in these possible effects of benefits and costs of territoriality influenced tenure, we manipulated local quality of oviposition substrate and perch density. The quality of oviposition substrate, but not perch density, influenced both potential benefits and costs of territoriality. Female density was higher in areas with good substrate, but so were rates of males intruding into the territories, rates of chasing by territorial males, and local density of territorial males. More matings occurred in areas with good substrate, but among males with tenures of 15 min or more, mating success per male and tenure lengths did not differ statistically among treatments. Defense costs were low for all treatments and perhaps were not an important influence on tenure duration. Territorial males in this population probably adjusted local density to expected mating success by initial choice of site rather than by varying tenure length. Variation in tenure length at a site resulted, in part, from stochastic external factors, such as predation attempts.     

Habitat patch size and mating system as determinants of social group size in coral-dwelling fishes

It is thought that the size and dispersion of habitat patches can determine the size and composition of animal social groups, however, this has rarely been tested. The relationship between group size, the mating system, and habitat patch size in six species of coral-dwelling gobies was examined. For all species, there was a positive correlation between coral colony size and social group size, however the strength of this relationship varied among species. Paragobiodon xanthosomus exhibited the strongest relationship and a manipulative field experiment confirmed that coral colony size limited group size in this species. For other species including Paragobiodon melanosomus and Eviota bifasciata, either a highly conservative mating system (P. melanosomus), or increased mobility (E. bifasciata) appeared to disrupt the relationship between habitat patch size and group size. There was no consistent relationship between the mating system exhibited and group size among the species investigated. These results demonstrate that habitat patch size, mobility, and mating systems can interact in complex ways to structure group size even among closely related species.     

Body size and alternative mating tactics in the beewolf Philanthus zebratus (Hymenoptera; Sphecidae)

A study of the mating behaviour of males of the beewolf Philanthus zebratus revealed that in one population males display variability in mating tactics and that this variability is related to male body size. There was a tendency for large males to patrol the airspace above the nesting area while smaller males were territorial adjacent to it. The mean sizes of the two groups of males were significantly different, although the size ranges of the two groups overlapped. Only 2.5% of the males were observed to undertake both mating tactics, at different times. Observations are presented on daily and seasonal activity patterns and on the relative location of nests, territories, and patrolling males. A second population, with lower nest density, was observed for several days, revealing only territorial males. It is suggested that the presence of patrolling males is related to the higher nest density of the one population. The fact that patrolling males tend to be relatively large is possibly related to flight energetics or simply to the ability of large males to seize females, which are usually larger than males, in mid-air.