Settlement Patterns of Mediterranean Fruit Flies in the Tree Canopy: An Experimental Analysis

Males of the Mediterranean fruit fly, Ceratitis capitata (medfly), defend individual leaves of host and non-host trees as mating territories and attract females via production of a sex pheromone (a behavior termed ‘calling’). Males tend to aggregate within the tree canopy, and the present study examined the influence of (1) location and (2) resources on female visitation to male aggregations. Males were placed in screen-covered containers, which were suspended on field-caged trees at two locations selected to differ in only one of the following parameters: height above ground (low versus high), leaf density (sparse versus dense), distance to main trunk (canopy edge versus center), proximity to a food source (bird feces absent or present), and proximity to a host fruit (oranges absent or present). Females were released, and we periodically recorded the number of calling males in each of the test aggregations as well as the number of females sighted within 15 cm of each male aggregation. Male calling did not differ between treatments in any of the experiments. However, females were more frequently sighted near males calling (1) in dense foliage, (2) near the central trunk, (3) near bird feces, and (4) near oranges. In an additional experiment, we compared male settlement (in the absence of females) on leaves in the same sites used previously to determine the degree of congruence between the sexes in microhabitat use. Aside from the lack of center-edge effect, males displayed the same settlement patterns as females. In a final experiment, we found no effect of male calling on the distribution of other males: released males were sighted with equal frequency near cups containing mature, calling males and cups containing immature, non-calling males. Medfly lek behavior is discussed in light of these findings.     

Territorial and mating behavior ofXylocopa fimbriata F. andXylocopa gualanensis Cockerell from Costa Rica

The territorial and mating behavior of two Xylocopaspecies X. fimbriataF. and X. gualanensisCockerell from Costa Rica are described. Male territorial activity was common during February through April in the higher areas of a dry forest savanna. Both species maintained territories at the same location within hollows in the foliage of Ardesia revolutaH.B.K., a small evergreen tree which occurs commonly in the dry forest. Xylocopa fimbriatamaintained territories during early morning hours, whereas the territorial period for X. gualanensisoccurred during late afternoon. Males of both species infrequently marked territories. It is suggested that a secretion released from their mesosomal glands is wiped onto their legs during frequent leg-body and leg rubbing which occurs while males hover. The secretion is occasionally applied to marking points on vegetation by their secretion-contaminated legs. Males repeatedly marked select locations when females were near their territories regardless of whether females were searching nearby branches for nesting sites, gathering provisions, or passing through their areas. Some females oriented to and entered certain male territories. An example of female mate choice in selection of male territories is provided. Females flew into male territories from 2–4 cm down-wind of male scent-marked locations. As females approached these locations, males hovered downwind in close proximity to the females' approach path. As females hovered a few centimeters downwind of the scented focal point, males approached from downwind and mounted. The males behavior and the role of scent-marking in the reproductive behavior of lek polygyny is discussed.     

The influence of age and experience with conspecifics on territorial behavior inDrosophila melanogaster

Drosophila melanogastermales initiated aggressive behavior toward other males and defended territories several hours after they were able to court and mate females. Males that were 3 days or more posteclosion were more successful at holding territories than younger males. Three-day-old males established territories more readily and escalated more often against territory residents than males that were 1 day old. Residents did not usually force young males from territories until they were a few hours posteclosion. The development of territorial behavior was not affected by familiarity or prior exposure to females. Males held in isolation established territories more quickly and behaved more aggressively than males held in groups. Males that previously held territories were more likely to reestablish them after a disturbance.     

Lek Breeding and Territorial Aggression in White-eared Kob

Territorial aggression in a lek breeding population of white-eared kob (Kobus kob leucotis) was investigated in the Boma National Park region, southern Sudan. The frequency of aggression on leks was positively related to the number of females present, but generally declined over the course of the breeding season. Males fought most strenuously for central territories that were preferred by females. Males with females in their territories were more frequently engaged in fights than unaccompanied males. Such fights often induced females to leave their original partners, especially when large groups of females were involved. Territorial aggression led to damaging injuries in several instances, and mortality of breeding age males was disproportionately high. These results suggest that the intensity of aggression exhibited by territorial males was scaled to potential reproductive benefits.     

Territory and monogamy among Kloss' gibbons (Hylobates klossii) in Siberut Island, Indonesia.

Behavior of Kloss' gibbons was studied from July 1 to October 7, 1972 in Siberut Island, off the coast of western Sumatra, Indonesia. Reproductive groups are monogamous families with a mean family size of 3.4 individuals (n = 11 families). Such families occupy territories averaging 6.7 ha. Adults defend their territories only against members of the same sex. This intrasexual defense of territory maintains the monogamous mating system. Other social units were unmated resident females, unmated resident males, floating males, and a courting pair. Males establish territories before mating, perhaps with help from their parents. Males guard their families against predators. Females lead progression through the territory. Subadults remain peripheral to their families but other family members tend to remain within 10 m of one another.     

Interactions between adult robins and chicks belonging to other pairs

Adult robins are able to discriminate between chicks hatched in their own and in other territories. The latter are much less likely to be fed and are more likely to be attacked than the adult's own young. As chicks grow older they become less likely to beg at adults other than their parents. Adults rarely feed chicks from other territories unless they have fledged young of their own. Possible causes of these different responses are discussed and it is emphasized that these need not involve individual recognition. Males appear to be more likely than females to feed chicks hatching in other territories. This could be the result of the females learning about their chicks while brooding them. Males may benefit more, on average, from feeding other pairs' chicks than do females. There has been a previous report that robins are unable to make the discriminations reported in this paper and possible reasons for this discrepancy are discussed. It is conceivable that it reflects a difference between populations.     

Landmark Territoriality in the Neotropical Paper Wasps Polistes canadensis (L.) and P. carnifex (F.) (Hymenoptera: Vespidae)

Male Polistes canadensis and P. carnifex aggregate along crests of prominent ridges in Santa Rosa National Park, Costa Rica. At these sites males of both species defend territories (trees and shrubs) by chasing conspecific rivals. Territories do not contain nests or resources that are collected by females. Chasing by territorial males reduces the amount of time spent by intruders in a territory. I describe and contrast male territorial behavior of both species. Some male P. canadensis are territorial while others in the same area exhibit patrolling behavior, flying from one occupied territory to another. Males of P. carnifex exhibit territoriality only. Patrolling in P. canadensis is an outcome of relatively high male density along the ridge, rendering territories in short supply, as shown by the observation that experimentally vacated territories are seized rapidly by formerly patrolling males. Due to a high intraspecific intrusion rate, territorial male P. canadensis spend less time perching and more time flying and chasing intruders from their territories than do male P. carnifex. Males of these two species also differ in the placement of their territories along the ridgeline; P. canadensis occupy territories in saddles while P. carnifex occupy those at peaktops. I show that this divergent spatial pattern is not maintained by competitive exclusion of either species by the other, and I discuss alternative explanations for their separate spatial distributions. Comparative data suggest that males are territorial because females restrict matings to within territories, and I discuss alternative hypotheses to explain this bias in female behavior.     

Timing of mate-locating by males in relation to female activity in the carpenter beeXylocopa varipuncta (Hymenoptera: Apidae)

Males of the carpenter beeXylocopa varipuncta Patton wait for females to visit them as they hover at landmark territories along ridgelines on some spring afternoons. While hovering, males advertize their presence by releasing a pheromone that attracts passing females. If males have limited time to invest in territorial hovering and signaling, then they should engage in these activities more often at times when mate-searching females are most likely to visit landmark territories. The number of females flying near male territories varies greatly over the course of afternoons and from day to day. Measures of female activity and male territorial activity were highly correlated at one study site, both in terms of changes within afternoons and in terms of day-to-day fluctuations. This result supports the hypothesis that males ofX. varipuncta time their mateattracting behavior to maximize contacts with receptive females.     

Male foraging avoidance in female feeding territories in a harem polygynous cichlid in Lake Tanganyika

We studied foraging site partitioning between the sexes in Neolamprologus tetracanthus, a shrimp-eating Tanganyikan cichlid with harem-polygyny. Females maintained small territories against heterospecific food competitors within large territories of males, foraging exclusively at the inner side of their own territories (foraging areas). Males fed as frequently as females in their own territories, but mostly outside female foraging areas, although they frequently entered female territories and repelled food competitors from the territories. Soon after removal of the resident females, however, harem males, as well as many food competitors, invaded the vacant territories and intensively devoured prey of female foraging areas. This indicates that although female foraging areas appear to contain more food than outside the areas, harem males refrained from foraging there when the resident females were present. We suggest that harem males will attempt to keep female foraging areas in good condition, whereby they may get females to reside in male territories and/or promote female gonadal maturation.     

Spawning Behavior and Biparental Egg Care of the Crosshatch Triggerfish, Xanthichthys mento (Balistidae)

Reproductive ecology of the crosshatch triggerfish, Xanthichthys mento (Balistidae) was studied at Hachijojima, Izu Islands, Japan. Males established territories and repeatedly chased females passing nearby. There were 1–3 females in each male's territory before spawning and during egg care. This species spawned in pairs on the sandy bottom. Eggs were scattered and attached to sand particles. Females care for the eggs by blowing water on them and guarding them against intruders, while males helped in guarding. Thus, biparental egg care was observed for 2 days until hatching. Both the males and females disappeared from the territories after the egg care. The reproductive ecology of this species is compared with that of other balistids and the unique features of X. mento are described.     

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.

     

Male behaviour and female choice: Mate selection in the wren?

The European wren is frequently polygynous. Males occupy exclusive territories within which they spend much time displaying and building nests. They lead females to their nests in courtship. Males building the most nests during a season also make the most breeding attempts. Data collected in one of two years suggested that individual females may show a preference for males with the largest number of complete but vacant nests. There was no consistent correlation between male display behaviour and female mate choice. Data on breeding success may suggest why polygyny is adaptive for both males and females in this species.     

The social and mating system of the maternal mouthbrooderTropheus moorii (Cichlidae) in Lake Tanganyika

Territorial behaviour, reproduction and migration of the epilithic algal eater,Tropheus moorii, were investigated in Lake Tanganyika, Africa. Adults of both sexes had individual feeding territories which adjointed each other. Males, who occupied higher rocks than females, usually stayed at the same sites for more than 5 months. Females left their territories to pair with males in the males’ territories. Paired females actively foraged under the protection of their mates for up to 3 weeks prior to spawning. After spawning, females usually settled in a site unoccupied by territory-holders to mouthbrood the offspring for a month. An examination of the ovaries and a removal experiment of dominant males suggest that females cannot attain fully mature ovaries in their own territories and choose males whose territories can provide enough food to satisfy their nutritive demand. The evolution of a number of local colour morphs in this fish is briefly discussed in relation to social selection.     

Temporal shifts in the pair-bond dynamics of New Zealand robins (

Winter is a challenging time for temperate insectivorous songbirds, due to colder temperatures, reduced prey activity and shorter diurnal foraging times. For species that are non-migratory, territorial and monogamous, winter conditions may result in within-pair competition. However, little is known about how monogamous pairs coexist on their winter territories. We investigated temporal patterns in male?female interactions of the New Zealand robin (Petroica australis to better understand mechanisms of coexistence during winter. Previous work has shown that male robins are physically dominant over females and maintain priority access to food year-round. We quantified female behaviour throughout the 2008 non-breeding season to better understand how females coexist with physically dominant males on winter territories. Results showed that pairs rarely forage in close proximity in autumn and winter, suggesting females avoid males at this time of year. Males and females begin to spend more time foraging together as winter turns to spring. During this winter?spring transitional period, females steal large amounts of food hoarded by males. These results indicate that male and female New Zealand robins use different behavioural mechanisms to coexist on their winter territories. While males are dominant physically, females show a seasonally variable strategy where they avoid males in autumn and winter, and then steal male-made caches from early spring until the onset of inter-pair cooperation and the breeding season.     

Feeding-site utilization in three sympatric species of Petrotilapia (Pisces, Cichlidae) from Lake Malawi

Three sympatric sibling species of Petrotilapia , with similar dietary and macrohabitat requirements, occur near Monkey Bay, Lake Malawi. Males and females of all three species fed selectively on the rocky shores. Males utilized less than 6% of the space they defended as a breeding territory for feeding and although interspecific overlap of territories was considerable, only 2.5% of the feeding space used by territorial males was shared. Males primarily utilized rich food patches which occurred within the territories of highly aggressive Pseudotropheus species, whereas females tended to feed in undefended areas. Although Petrotilapia species are not highly aggressive fishes, there was a well-defined social dominance hierarchy amongst them and it is suggested that feeding-site utilization is dependent on social rank. Inter-and intraspecific differences in feeding-site utilization probably facilitate species coexistence and thus contribute to the maintenance of the high species diversity which is a characteristic of the ichthyofauna of Lake Malawi.     

Reproductive Behaviour of Japanese Tubesnout, Aulichthys japonicus (Gasterosteiformes), in the Natural Habitat Compared with Relatives

We observed significant sexual dimorphism in size (females > males) and in colour in Japanese tubesnout, Aulichthys japonicus, in Aburatsubo Bay, central Japan, and Otsuchi Bay, northern Japan. This species is known to spawn its eggs into ascidians. We observed reproductive behaviour of tubesnout in the natural environment in both bays. All the males established territories at harbours or rocky shores and showed conspicuous nuptial colouration with metallic green or blue on their snout and bright yellow on the body. Females had a dark brown body with remarkable white spots. The male territories varied somewhat in location and extent on a daily basis. The individual male size and territory size were not correlated. The females usually stayed in the seaweed beds where no males were present. Males and females were distributed separately, and the gravid females visited the male territories in groups to spawn. The territorial males courted the gravid females by rushing and returning, and tried to lead the females to the particular place of their territories by tail beating. We discuss nuptial colouration, courtship behaviour and territoriality in comparison to the related species; Aulorhynchus flavidus, Hypoptychus dybowskii, and gasterosteid fishes.     

INTRASEXUAL COMPETITION ALONE FAVORS A SEXUALLY DIMORPHIC ORNAMENT IN THE RUBYSPOT DAMSELFLY HETAERINA AMERICANA

I studied the sex-limited red spots on the wings of male rubyspot damselflies (Hetaerina americana) in relation to territoriality and fitness in the wild. Both observational and experimental (wing spot manipulation) studies indicated that wing spots were selected through competition among males for mating territories, not through female choice or direct competition for females. Males with naturally or artificially large wing spots were more successful at holding territories and consequently mated at higher rates than males with relatively small wing spots. In contrast, sexual selection on male body size appeared to operate among nonterritorial males at the clasping stage of the mating sequence, perhaps because larger males were better at clasping females forcibly. Of four models proposed to explain the evolution of ornaments through territory competition, only the agonistic handicap model makes predictions consistent with the results of this study.     

Off-territory movement of male American Redstarts (Setophaga ruticilla) in a fragmented agricultural landscape is related to song rate, mating status and access to females

Male songbirds often move off-territory to pursue extra-pair fertilizations. This movement represents a trade-off between paternity gain and loss and can be influenced by male quality and access to fertile females. Access to females could be reduced in fragmented landscapes that have small patches and low connectedness. We studied movement and extra-pair fertilization success of radio-tracked male American Redstarts (Setophaga ruticilla) in forest patches in an agricultural landscape in Alberta, Canada, over 2 years. Males spent an average of 18% of their time off-territory, mostly intruding onto adjacent territories and rarely moving between patches. They averaged 0.8 trips/h, with mean trip duration of 17 min and mean trip distance of 104 m. Less time was spent off-territory when their mate was nest-building and males intruded most often onto territories with nest-building females. Males with higher song rates and more nearby females intruded most onto other territories. Monogamous males in better condition with higher song rates spent the most time off-territory. However, males with more nearby females and higher local breeding synchrony spent the least time off-territory, suggesting these males face a trade-off between seeking extra-pair fertilizations and protecting against cuckoldry. Forest cover was not an important predictor of movement. Investment in off-territory movement did not predict extra-pair fertilization success or probability of cuckoldry. However, few tracked males achieved extra-pair fertilizations (1/22 tracked males vs 18/57 non-tracked males), possibly an artefact of low sample size or the effect of radio transmitters on female choice.     

Spatial distributions of male and female strawberry poison frogs and their relation to female reproductive resources

In many species with a resource-based mating system, males defend resources to increase their attractiveness to females. In the strawberry poison frog, Dendrobates pumilio, suitable tadpole-rearing sites appear to be a limited resource for females. Territorial males have been suggested to defend tadpole-rearing sites to increase their access to females. In this study we investigate the spatial association between tadpole-rearing sites and the sexes as well as the spatial association of males and females. If strawberry poison frogs have resource defense polygyny, we expect males and females to be associated with tadpole-rearing sites and that females will deposit their offspring in tadpole-rearing sites inside the territories of their mates. To test this hypothesis, home range and core area sizes were calculated for both sexes and the association patterns were compared in two areas that differed in their abundance of tadpole-rearing sites. Home ranges and core areas of females were much larger than male home ranges. Females showed a clumped distribution in the vicinity of tadpole-rearing sites. Males were not clumped and were less associated with tadpole-rearing sites. Females generally did not use tadpole-rearing sites in the territory of their mates and we therefore conclude that males did not defend tadpole-rearing sites for females. Our data are consistent with the general assumption that female distribution is influenced by resource distribution and that male distribution depends on female distribution. Nevertheless, the distribution of D. pumilio females was also influenced by male spacing patterns. Males probably initially establish their core areas where female density is high and then females move among territories to sample males. Males compete vigorously for places with high female density, the defense of which is likely important for enhancing their mating success. In general, the spacing patterns did not differ between populations but the sex ratio was strongly female biased in the habitat with more tadpole-rearing sites, reflecting the direct reliance of females on these resources.     

Spatial organization of the North Island Brown Kiwi Apteryx australis mantelli: sex, pairing status and territoriality

In Waitangi State Forest, 51 North Island Brown Kiwi Apteryx australis mantelli were tagged with radio transmitters and observed for an average of 2.3 months. All females and the majority of males were paired and maintained territories of 6.7 and 5.5 ha, respectively. Territories overlapped widely between partners but only narrowly with those of paired neighbours. Unpaired males had territories of 12.8 ha and extensively overlapped those of paired males. Territories were maintained by long distance calls and rare aggressive encounters. Males were more territorial than females. Within pairs, males called 1.5 times more often than females and initiated most pair calls. 60% of female calls were responses to their mates. Observers could often induce aggressive behaviour (calling, fast approach) in male kiwi (by playback, for example) but hardly ever in females. Kiwi territoriality cannot be explained by the distribution and availability of food and shelter sites, but seems to serve mainly a reproductive function.