Territories of male and female terrestrial salamanders: costs,benefits, and intersexual spatial associations

Summary I used a mark-recapture study to estimate home areas for 107 red-backed salamanders (Plethodon cinereus) in a natural forest habitat. Both males and females of this species defend feeding territories, but I presume that some individuals in this relatively highdensity population (approximately 2.8 salamanders per m²) are nonterritorial floaters. Although territorial salamanders exhibited greater numbers of tail autotomies, they had significantly longer relative tail lengths. This difference suggests that territorial individuals gain benefits from territorial ownership. From the observation that home area size was inversely correlated with body size, I infer that larger animals gained higher quality foraging areas. Home areas of adults were significantly more segregated intrasexually and more aggregated intersexually than would be expected from a random distribution. Furthermore, intersexual overlap of home areas was significantly greater than intrasexual home area overlap. Territorial defense of feeding areas by male and female red-backed salamanders therefore also may play a role in mating behavior.     

Thermal effects on activity patterns and behavioural switching in a concourse of foragers on Stachytarpheta mutabilis (Verbenaceae) in Papua New Guinea

Summary 1. The foraging activities of the papilionid butterflies Ornithoptera priamus poseidon and Papilio ulysses, and the solitary bee Amegilla sapiens (Apoidea, Anthophoridae) on the shrub Stachytarpheta mutabilis were studied in highland Papua New Guinea. 2. The insects' activity patterns were analysed at three sites with differing diurnal microclimate variation. O. priamus and A. sapiens foraged in the morning (after a period of basking and wing-whirring) and late afternoon when temperatures were well below daily maxima, whereas P. ulysses showed foraging peaks during the hottest part of the day. 3. Site choice by all 3 species appeared to be determined primarily by temperature, but within the limits imposed by temperature, nectar supplies probably determined which site was visited. 4. P. ulysses showed interspersed foraging and courtship behaviour, and no behavioural switching was observed for this species. At high temperatures, both O. priamus and A. sapiens ceased foraging and showed territorial and courtship behaviour. This behavioural change allowed avoidance of heat stress, and occurred even when nectar supplies were maintained at high levels. 5. Thermal effects on behavioural switching in these insects are compared with related phenomena in other bees and butterflies.     

Pair behavior and spacing in butterflyfishes (Chaetodontidae)

Synopsis Three species of butterflyfishes, Chaetodon multicinctus, C. quadrimaculatus and C. ornatissimus were observed over a seven month period on the Kona coast of the island of Hawaii. All three species were found to be exclusively paired. However, C. quadrimaculatus and C. ornatissimus pair mates spent less time together and had longer separations and fewer meetings than did C. multicinctus pairs. All three species occupied and defended intraspecifically exclusive territories. Territories were maintained through mutual avoidance with occasional agonistic interactions.     

A growth/mortality trade-off in larval salamanders and the coexistence of intraguild predators and prey

Behavioral and morphological traits often influence a key trade-off between resource acquisition and vulnerability to predation, and understanding trait differences between species can provide critical insight into their interactions with other species and their distributions. Such an approach should enhance our understanding of the criteria for coexistence between species that can interact through both competition and predation (i.e. intraguild predators and prey). I conducted a common garden experiment that revealed strong differences between three guild members (larval salamanders Ambystoma laterale, A. maculatum, and A. tigrinum) in behavior, morphology, and growth in the presence and absence of a shared top predator (the larval dragonfly Anax longipes). All three species also reduced their activity and modified their tail fin depth, tail muscle length, and body length in response to non-lethal Anax. Species that act as intraguild predators were more active and could grow faster than their intraguild prey species, but they also suffered higher mortality in laboratory predation trials with Anax. I also used survey data from natural communities to compare the distribution of Ambystoma species between ponds differing in abiotic characteristics and predatory invertebrate assemblages. An intraguild prey species (A. maculatum) was found more reliably, occurred at higher densities, and was more likely to persist late into the larval period in ponds with more diverse invertebrate predator assemblages. Taken together, these results indicate that top predators such as Anax may play an important role in influencing intraguild interactions among Ambystoma and ultimately their local distribution patterns.     

Winter territoriality and fruit defence by the fieldfare ( Turdus pilaris )

During the winter seasons of 2000/2001 and 2003/2004, 27 territorial fieldfares Turdus pilaris were observed in two study areas in southern Poland. Of these, 22 were in gardens or orchards with apple trees. Only 0.5% of all fieldfares noted during field surveys were territorial, and only 1.7% of the checked gardens and orchards were inhabited by that species. Fieldfares defended fruit against several species, including conspecifics. The probability of the presence of territorial fieldfares within a habitat patch was higher in patches with a higher density of apples, but was not related to the size or degree of isolation of the patch. The duration of holding territory was positively correlated with apple density and negatively correlated with the presence of intruders (mainly flocks of non-territorial fieldfares). The results suggest that food density and the presence of intruders are key factors affecting the presence of territorial thrushes during winter.     

Host preferences ofTrichogrammatoidea bactrae fumata (Hym.: Trichogrammatidae) an egg parasitoid of leafrollers (Lep.: Tortricidae)

Trichogrammatoidea bactrae fumata Nagaraja is a naturally occurring egg parasitoid of some leafrollers in New Zealand kiwifruit orchards. The parasitoid showed a distinct preference for younger host-eggs ofEpiphyas postvittana, in which it achieved a higher rate of successful development. Such a preference is not as apparent withCtenopseustis obliquana. Host-species preference experiments found that the parasitoid rarely attackedPlanotortrix octo, and successful wasp emergence from parasitised eggs of this host was low.Epiphyas postvittana was the preferred host whenT. bactrae fumata was reared on this species. When reared onC. obliquana, the parasitoid showed no preference forE. postvittana orC. obliquana.     

Hand preferences in captive orangutans (Pongo pygmaeus)

The strength of the evidence for population-level handedness in the great apes is a topic of considerable debate, yet there have been few studies of handedness in orangutans. We conducted a study of manual lateralization in a captive group of eight orangutans (Pongo pygmaeus) ranking the degrees of manual preference according to a defined framework. We analyzed five behavioral patterns: eat (one- and two-handed), make/modify tool, oral tool-use, and manual tool-use. Although some individuals showed significant manual preferences for one or more tasks, at the group-level both one-handed and two-handed eating, oral tool-use, and make/modify tool were ranked at level 1 (unlateralized). Manual tool-use was ranked at level 2, with four subjects demonstrating significant hand preferences, but no group-level bias to the right or left. Four subjects also showed hand specialization to the right or left across several tasks. These results are consistent with most previous studies of manual preference in orangutans. The emergence of manual lateralization in orangutans may relate to more complex manipulative tasks. We hypothesize that more challenging manual tasks elicit stronger hand preferences.     

Impact of predation by spiders on a territorial damselfly (Odonata: Calopterygidae)

Summary Predation by orb-weaving spiders and crab spiders on the damselfly Calopteryx haemorrhoidalis was studied at a small stream in Southern France. One species of orb-weaving spider, Larinioides folium, caught 76% of the damselflies which fell prey to spiders. Displacement experiments on spiders on sections of bank and the positioning of webs in male territories show that the density and distribution of damselflies is not influenced by orbweb density or by the position of webs. Predation rates corresponded to orb-web density, but neither for sex nor for stage was there a relationship with damselfly density. Mean daily predation rates ranged between 0.9% for females and 4.1% for adult males. Predation risk to adult damselflies by orb-weaving spiders was male biased, whereas among tenerals there was no bias. Males were captured more frequently at territories near the water. Captures show a maximum at noon when territorial disputes of adult males were most frequent. After orbwebs were placed within territories predation rate of males was strongly increased. Predation risk to adult females in the direct vicinity of the stream was less than in the bank vegetation where they perch close to orbwebs. The risk of predation by crab spiders, which catch damselflies at their perching sites, was not sex-biased.     

The inveterate wanderer: study of Enhancer wandering on chromosome 3 in maize

The transposition of the maize transposable element Enhancer (En) had been focused on one chromosome 3 for several generations. From the a1-m(Au) allele with an autonomous En, a new En reporter allele a1-m(r)3927-1, was isolated that undergoes very infrequent and late excision events, producing one or two small spots in the aleurone. This allele is seriously impaired in its capacity to excise. Coincident with the origin of this allele, an En was located at a site close to the a1 locus. From this initial insertion site, the movement of this En was followed for three to four generations in 974 families with a higher transposition rate of this En (50% of the testcross progeny) than that found in a previous study of En transposition. This is the first case reported where a particular En was followed for more than three generations. The higher rate of wanderings of this En along the same chromosome led to the term vagabond En (En ^vag ). Genetic evidence that En may transpose from a replicated donor site to an unreplicated site is provided. Speculative mechanisms on the origin of a1-m(r)3927-1 and En ^vag are discussed.Journal Paper No. J-15864 of Iowa Agricultural and Iowa Economical Experiment Station Project #3176     

Spacing behaviour and habitat use of rock ptarmigan (Lagopus mutus) at low density in the Italian Alps

Studies of rock ptarmigan Lagopus mutus in northern latitudes have shown that, in the breeding season, the majority of cocks pair monogamously and defend small territories, whilst in most populations, a small proportion of cocks are polygynous or remain unmated. Little is known, however, on spacing behaviour and habitat use of alpine rock ptarmigan populations occurring at low densities at the southern edge of the species’ range. From 1995 to 1997, we trapped, radio-tracked and observed birds in the Central Italian Alps (elevation 2,000–3,000 m) in order to investigate spacing behaviour and habitat use in alpine landscapes where habitats offering rich food and cover are patchy. Both sexes were selective in their habitat use, and cocks did not establish territories on bare ground, artificial or nutrient rich grasslands or bogs. In the breeding season, cocks had larger home ranges than hens (cocks 99 ± 57 ha, hens 50 ± 25 ha) that overlapped with the ranges of neighbouring cocks and hens. Cocks were monogamous and defended relatively large territories (core areas of home ranges: cocks 37 ± 26 ha, hens 24 ± 12 ha), which corresponded with low spring densities (0.47–2.29 cocks km⁻² and 0.35–1.60 pairs km⁻²). Territory size of individual cocks was negatively correlated with the amount of high quality habitat in the core-area. Our results suggest increased home ranges and large breeding territories in low density alpine rock ptarmigan populations, compared to populations occurring at higher densities in the central and northern alps, and on subarctic and arctic grounds at northern latitudes, confirming the predictions of models on food-based territoriality.     

Molecular evidence for historical and recent population size reductions of tiger salamanders (Ambystoma tigrinum) in Yellowstone National Park

Population declines caused by natural and anthropogenic factors can quickly erode genetic diversity in natural populations. In this study, we examined genetic variation within 10 tiger salamander populations across northern Yellowstone National Park in Wyoming and Montana, USA using eight microsatellite loci. We tested for the genetic signature of population decline using heterozygosity excess, shifts in allele frequencies, and low ratios of allelic number to allelic size range (M-ratios). We found different results among the three tests. All 10 populations had low M-ratios, five had shifts in allele frequencies and only two had significant heterozygosity excesses. These results support theoretical expectations of different temporal signatures among bottleneck tests and suggest that both historical fish stocking, recent, sustained drought, and possibly an emerging amphibian disease have contributed to declines in effective population size.     

Grooming site preferences in female langurs (Presbytis entellus)

Factors influencing grooming site preferences in adult female Hanuman langurs (Presbytis entellus) were investigated. The females belonged to a free-ranging harem troop (Jodhpur, India) and were observed for 569 hr by focal-female sampling. Decisive factors for grooming site preferences were the following: autogrooming was determined mostly by site accessiblity. Allogrooming was significantly concentrated on parts that are inaccessible to the groomee. Close female kin groomed significantly longer, more frequently, and more precisely at inaccessible body parts. Lower-ranking females were groomed significantly less often and more briefly but also more precisely at inaccessible parts. However, the latter might be due to a lower-ranking subjects desire to face away from the higher-ranking groomer in order to avoid eye contact. The data suggest that the groomee determines the sites being groomed.     

Habitat preferences of tree pipit ( Anthus trivialis) and meadow pipit ( A. pratensis) at sympatric and allopatric localities

Habitat preferences of the tree pipit (Anthus trivialis) and the meadow pipit (A. pratensis; Passeriformes: Motacillidae) were observed during the years 1998–1999 at three localities in the Czech Republic; two with one pipit species only, and a third with both species present. We investigated one of the possible mechanisms allowing syntopic coexistence—different habitat selection. We characterised territories of each pipit pair by the habitats present in the territory (defined by dominant plant composition) and by quantitative parameters (territory size, height and density of the vegetation, number of look-outs of different height categories, and proportion of wet ground). Tree pipits preferred significantly higher vegetation of lower density than meadow pipits, and there was generally a higher number of high look-outs in their territories. However, in some of the preferred territories at the allopatric locality of the tree pipit, steep hill slopes could well substitute for higher look-outs, which were almost absent. The two pipit species at the sympatric locality occupied very different habitats, which was also reflected in quantitative parameters of their territories. The available data of pipit habitat at different European localities show that the two species can occupy a much wider range of habitats. The habitat separation in sympatry might therefore be one of the mechanisms allowing syntopic coexistence of both species.Communicated by F. Bairlein     

Temperature preferences and oxygen consumption of three species of sculpin (Cottus) from the Pit River drainage,California

Synopsis I examined the temperature preferences and routine metabolic rates of Pit sculpin, Cottius pitensis, marbled sculpin, C. klamathensis macrops, and rough sculpin, C. asperrimus, of the Pit River drainage of California to determine if the distributional patterns of these species can be explained on the basis of physiological or behavioral responses to temperature. The routine metabolic rates of these species did not increase significantly between 10 and 15°C, indicating an area of thermal compensation. Metabolic rates then rapidly increased between 15 and 20°C (Q₁₀ values>4.0) followed by little increase between 20 and 25°C (Q₁₀ values >2.0), indicating another area of thermal compensation. The final temperature preferenda of Pit, marbled and rough sculpin were 11.2, 12.1 and 13.5°C, respectively. Marbled and rough sculpin appear to be more stenothermal than Pit sculpin. At acclimation temperatures of 10, 15 and 20°C the acute preferred temperatures of marbled and rough sculpin ranged from 11.1 to 14.7° C and 13.3 to 14.4°C, respectively. Values for Pit sculpin ranged from 9.9 to 16.4°C at acclimation temperatures of 10, 15 and 20°C. The distributions of marbled and rough sculpin are consistent with their behavioral and metabolic responses to temperature. The widespread distribution of Pit sculpin is consistent with its greater tolerance of high temperatures and eurythermal behavior, but the absence of Pit sculpin from habitats dominated by marbled and rough sculpin is not consistent with a temperature related explanation.     

Traditional and diversified crops in South Moravia (Czech Republic): Habitat preferences of common vole and mice species

Substantial changes in the composition of crops in Central Europe during the last two decades (increasing areas of maize, rape and sunflower fields) have significantly influenced the structure and dynamics of animal communities, though there is a lack of data available for small rodents. In this study, we assessed the importance of these three crops for rodents and compared it with traditional crops (alfalfa, barley, wheat). We observed that herbivorous species (especially the common vole) do not live in crops which do not have green leaves near the ground (e.g. sunflower, maize), while mobile granivorous species can inhabit all types of crop. We confirmed the presumed differences in habitat preferences; however we rejected the hypothesis of a general increase of rodent abundance during the vegetative season in managed fields. We found that (1) maize and sunflower had no importance for common voles, but they were favored habitats for wood mice; (2) numbers of wood mice in rape decreased during the season, while abundances of common voles increased; (3) common vole populations tended to increase during the season in all suitable crops (alfalfa, barley, wheat, tendency in maize and rape); (4) wood mice populations seemed stable in all crops; i.e. without a seasonal increase. It can be concluded that even if the new crop fields are an important part of the agricultural landscape, they are only a temporal habitat for small mammals, especially granivorous species.     

A study of correlates of hand preferences in squirrel monkeys (Saimiri sciureus)

The purpose of this study was to test the influence of sex, age, social rank, matriline membership, posture, and visual and tactual motor control on manual preferences inSaimiri sciureus. A well-established social group of 12 squirrel monkeys, aged 2 to 14 yrs and consisting of two matrilines with social rank known for each animal, was presented with four different food-reaching tasks and assessed for hand preferences with a minimum of 100 reaches per animal. Frequency of occurrence of hand preferences at the group level and degree of hand preferences at the individual level depended on posture and on whether the reaching act took place under visual or tactual guidance. Sex, age, social rank, and matriline membership were not found to determine frequency of occurrence, direction or degree of hand preferences with the exception of one task in which a significant negative correlation between the degree of hand preference and age was found. Nine out of 12 monkeys showed task-dependent changes in the hand they used preferentially while only three animals preferred the same hand in all four tasks. Significant preferences for the use of right or left hand on a given task were distributed almost equally between individuals. Thus, the results of this study suggest task-specific demands like posture and/or whether reaching was visually or tactually guided to be the major correlates of hand preferences in food-reaching tasks in squirrel monkeys.     

Territory defense by the ant Azteca trigona: maintenance of an arboreal ant mosaic

Mosaics of exclusive foraging territories, produced by intra-and interspecific competition, are commonly reported from arboreal ant communities throughout the tropics and appear to represent a recurring feature of community organization. This paper documents an ant mosaic within mangrove forests of Panama and examines the behavioral mechanisms by which one of the common species, Azteca trigona, maintains its territories. Most of the mangrove canopy is occupied by mutually exclusive territories of the ants A. trigona, A. velox, A. instabilis, and Crematogaster brevispinosa. When foraging workers of A. trigona detect workers of these territorial species, they organize an alarm recruitment response using pheromonal and tactile displays. Nestmates are attracted over short distances by an alarm pheromone originating in the pygidial gland and over longer distances by a trail pheromone produced by the Pavan's gland. Recruits are simultaneously alerted by a tactile display. No evidence was found for chemical marking of the territory. Major workers are proportionally more abundant at territory borders than on foraging trails in the interior of the colony. The mechanisms of territory defense in A. trigona are remarkably similar to those of ecologically analogous ants in the Old World tropics.