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Increased sociality in herons, family Ardeidae, is often considered to be associated with the occurrence of white plumage. If white plumage increases sociality, we hypothesized that white-plumaged birds should forage closer to one another and dark birds should remain more solitary. We tested this hypothesis by investigating the inter-individual spacing (nearest neighbor distance) in two pairs of closely related species that differ in plumage coloration: (1) Great Blue Heron (Ardea herodias)/Great Egret (A. alba) and (2) Little Blue Heron (Egretta caerulea)/Snowy Egret (E. thula). All birds observed were in adult plumage. We recorded distances to nearest conspecific, nearest congeneric, nearest white (regardless of species) and nearest dark bird to each focal bird within a given (focal) pond. Because species occurred in varying numbers, we compared the observed mean distances with randomly generated distances based on the total number of birds in the pond. All observations were conducted under steady water levels, avoiding drying ponds as this might concentrate prey. We found that Snowy Egrets were significantly farther from conspecifics and dark congenerics (Little Blue Herons) than expected under a null model of random spacing within the focal pond. Little Blue Herons also were spaced farther apart from white congenerics (Snowy Egrets) than expected. Great Blue Herons and Great Egrets exhibited no distinct social tendencies and neither avoided nor preferred foraging near other herons. Our results do not support the hypothesis that white-plumaged birds exhibit increased social tendencies relative to dark-plumaged birds within a given pond.

A study on achievement of coordinated cultural divergence by groups, using coordination games, is presented.

A test was conducted to investigate if mother--infant social transmission plays a role in the acquisition of subterranean habits in the rodent Ctenomys talarum. Thirteen infants were reared by their mother in an experimental aboveground habitat that precluded burrow construction. At the age of natal dispersal, young were allowed to dig in the soil typically inhabited by the species. All experimental tuco-tucos engaged in burrowing activities after short latencies (51 s [+ or -] 35 SD). Aboveground excursions lasted a few seconds and covered short distances, and there were no significant differences between experimental and control wild tuco-tucos. The structure of the burrows constructed by experimental tuco-tucos did not substantially differ from those typical for the species. It is concluded that vertical social transmission is not essential for the development of subterranean habits in C. talarum. The results are discussed regarding growing evidence on social transmission and its alleged role during evolution. Key words: Ctenomys, niche construction, ontogeny, social leaming, subterranean rodents

We examined the spatial and social structure of a high-altitude population of the scarcely known southern mountain cavy (Microcavia australis) in Argentina. We used radiotelemetry techniques to monitor nest use at night and daily home ranges and examine whether southern mountain cavies form nesting associations that are socially cohesive groups. We further timed our observations to breeding time of our study population (September-November) to assess opportunities for communal breeding. The nighttime telemetry of 24 radiotagged cavies revealed 7 nesting associations (i.e., communal nesting). These included 1-4 breeding females and 1 or 2 breeding males. Nesting associations were stable in terms of identity of individual members and in the location of putative nest sites. Most associations used a single nest site, but some shared 2 of 3. We noted that all nest sites were located under dominant shrubs, but use of nest sites was unrelated to variation in shrub cover. Nest sites with more burrow entrances were more frequently used by radiocollared cavies. During the day, home ranges of cavies overlapped more with ranges of nest mates than with those of non--nest mates, implying that nesting groups were socially cohesive units. This study confirmed that southern mountain cavies are communally nesting, and, because communal nesting occurs during breeding time, our findings support the idea that cavies engage in communal care of young. Key words: communal nesting, group living, home-range overlap, home-range size, Microcavia, nest site, nest use, social structure, southern mountain cavy, space use

Caribbean spiny lobsters display a diversity of social behaviors, one of the most prevalent of which is gregarious diurnal sheltering. Previous research has demonstrated that shelter selection is chemically mediated, but the source of release and the identity of the aggregation signal are unknown. In this study, we investigated the source and specificity of the aggregation signal in Caribbean spiny lobsters, Panulirus argus. We developed a relatively rapid test of shelter choice in a 5000-1 laboratory flume that simulated flow conditions in the spiny lobster's natural environment, and used it to examine the shelter preference of the animals in response to a variety of odorants. We found that both males and females associated preferentially with shelters emanating conspecific urine of either sex, but not with shelters emanating seawater, food odors, or the scent of a predatory octopus. These results demonstrate specificity in the cues mediating sheltering behavior and show that urine is at least one source of the aggregation signal., Introduction Many species of palinurid lobsters display gregarious social behaviors (Atema and Cobb, 1980). In the Caribbean spiny lobster, Panulirus argus, this sociality is evident in a variety of behaviors [...]

The discovery of genetic caste determination (GCD) in populations of Pogonomyrmex harvester ants raises many questions about the evolution and persistence of such populations. The genetic caste determination arises from the existence of two distinct, but mutually dependent, genetic lineages within a population. Workers always develop from a combination of the two lineages, but their sister queens develop from within-lineage matings. Maintaining genetic caste determination appears to be costly because many queen-destined eggs are wasted when a colony is not in the reproductive stage, yet these populations appear to be widespread. We investigated whether inter-lineage workers have novel traits that give GCD colonies a selective advantage in certain environments. In particular, we compared ecologically relevant behavioral characteristics of inter-lineage workers in H-lineage colonies with cooccurring normal colonies of P. rugosus. First, we measured colony defensive response toward a simulated vertebrate predator. Second, we set up direct competitive foraging and recruitment experiments between dependent lineage and P. rugosus colonies. Last, we measured individual aggressive response to foreign inter-lineage and P. rugosus workers. We found that H1/H2 inter-lineage workers explored objects on the nest more thoroughly and responded much more aggressively to simulated predator disturbance than the P. rugosus colonies. In individual encounters, H1/H2 inter-lineage and P. rugosus workers were equally aggressive toward foreign ants, but both worker types could discriminate P. rugosus from inter-lineage intruders and were more aggressive toward ants of the alternate type to themselves. When competing directly for resources, however, P. rugosus colonies consistently dominated seed piles. In summary, H1/H2 GCD colonies show distinct behavioral differences, but there is no clear ecological advantage from the traits we examined. Key words: aggression; foraging; genetic caste determination; harvester ants; hybridization; social hybridogenesis.

During group defense, the contribution of female black howler monkeys (Alouatta pigra) may help deter male intruders; however, their involvement during natural intergroup encounters is facultative. Experimental playback trials simulating potentially infanticidal males were used to examine whether a female's reproductive investment and/or her group's relative fighting ability would influence her participation in loud call displays. Female howlers never responded to recordings without alpha male accompaniment, but their response patterns did not simply mimic his. For example, unlike alpha males, females with small, vulnerable offspring were no more likely than females without infants to participate in howling displays during playback trials. Further, although females without any small infants in their group got closer to speakers than females living in groups with small infants, males did not respond in the same way. To artificially simulate different 'numeric odds' scenarios, recordings of one or three howling males (simulated intruders) were broadcast to females living in groups with 1-3 resident males. Responses were consistent with the hypothesis that females assessed intergroup fighting ability. As in alpha males, the weakest female responses occurred when the numeric odds were against their group. However, whereas alpha males participated most when numeric odds were in their favor, females had the most intense approach responses when the number of defending and intruding males was equal. Females appeared to use a cost-effective strategy, reserving their assistance for when their participation could have the greatest impact. KEY WORDS intergroup contests; displays; group-level fighting ability

This study investigated the effects of habitat on the diet, population density, and social structure of a small-bodied folivore, Hapalemur griseus. Three groups of H. griseus were followed at two study sites (Tala and Vato) within Ranomafana National Park in southeastern Madagascar. These two sites differed in degree of habitat disturbance, forest composition, and forest structure, as determined by botanical plots (50 x 10 m) which were monitored twice monthly in the home ranges of three study groups (group T, n = 4; group V1, n = 4; group V2, n = 2). Tala has experienced more habitat disturbance compared to Vato, and this appeared to influence population density and group size. The H. griseus that inhabit Tala occur at much higher densities and in larger social groups than the H. griseus at Vato. These results may be attributable to: 1) a greater number of potential food sources, 2) a more dense resource base, and/or 3) higher-quality resources at Tala for this folivore. In general, dietary diversity for all groups was low, and groups exploited similar plant species. However, within this small range of food sources, each study group specialized in food sources found in the highest abundance within their home range. This resulted in dietary differences between groups within sites, as well as differences between sites. Introduced tree species such as Chinese guava (Psidium cattleyanum) may have greatly impacted the diet and social structure of those groups at Tala, whose home ranges included this food source. In contrast, Vato group 1 ingested more new and mature leaves of Ficus spp., and Vato group 2 primarily ate spider bamboo (Nastus elongatus). In conclusion, it seems that microhabitat differences, which may be related to habitat disturbance and/or other factors such as topography, influenced the food species ingested by H. griseus. Overall habitat quality, which is likely also affected by habitat disturbance, influenced general diet, population density, and group size. KEY WORDS bamboo; habitat disturbance; group size; population density; folivory

A research work which suggests that the notion of the culture could be applicable to broader, more structural elements of the social behavior of a non-human group, one encompassing the notion of a social culture is reviewed. The research findings suggest that if two transfer males were to join at the same time and focus their energies upon exploitively competing with resident males rather than on defecting in conflict with each other, they might establish an atmosphere of aggression and non-affiliation that would push resident males toward similar behaviors.

A study of hygienic behavior of honey bees, Apis mellifera, in mixed colonies during removal of diseased brood to prevent disease transmission with relation to division of labor is presented.

A study on food sharing between peers in jackdaws, Corvus monedula, with relation to reciprocity, harassment avoidance is presented

A study on spontaneous cooperation in captive chimpanzees, Pan troglodytes, based on tolerance acts is presented.

The river otter (Lontra canadensis) has a complex social system, which varies widely across its range. We examined patterns of space use and social interactions for a native population of river otters in southeastern Minnesota. We radiomarked 28 river otters and monitored annual home ranges and core areas, static and dynamic interactions, and site fidelity. We compared these characteristics and interactions between sexes and age classes. Annual home ranges of male river otters were 3.2 times greater than those of females (P = 0.042), and annual core areas of males were 2.9 times greater than those of females (P = 0.083). The static interactions among river otters were extensive, with 69% of the individuals exhibiting core-area overlap. Overall dynamic interactions were positive (i.e., animals were closer together than expected). Males used 74% of their year 1 home range during year 2, and females used 75%. Females on average used only 39% of their core area from year 1 during year 2, whereas males used 65%. In general, conspecifics were not excluded from home ranges or core areas and signs of cooperation were evident, suggesting that river otters in southeastern Minnesota were social rather than territorial. Key words: core area, dynamic interactions, fidelity, home ranges, Lontra canadensis, river otters, sociality, static interactions, territoriality

We studied the home-range and core-area size and overlap of Tehuantepec jackrabbits (Lepus flavigularis) by radiotracking 32 individuals between May 2001 and April 2003 in savanna habitat in the Isthmus of Tehuantepec, Oaxaca, Mexico. Annual home-range and core-area sizes averaged 55 ha [+ or -] 8 SE and 8 [+ or -] 1 ha for 10 adults of both sexes using the 95% and 50% fixed-kernel isopleths, respectively. Seasonal home ranges varied widely for adults, from 15 to 111 ha for females and from 24 to 166 ha for males. Juvenile males had larger seasonal home ranges than did juvenile females ([bar.X] = 80 and 24 ha). For adult jackrabbits, seasonal home ranges were larger during the 1st year compared to those of the 2nd year of study ([bar.X] = 87 and 49 ha), particularly for females. Home ranges and core areas of Tehuantepec jackrabbits were comparable in size and overlapped between active periods (nocturnal and crepuscular hours) and inactive periods (diurnal hours). Adults overlapped their home ranges with 1-10 individuals. Home-range overlap among females was greater than among males. Females shared portions of their ranges with other females more frequently than did males with other males. Home-range and overlap analysis suggests that Tehuantepec jackrabbits have polygamous mating behavior and nonterritorial social organization. Key words: home range, Lepus flavigularis, mating, Mexico, overlap, social behavior, Tehuantepec jackrabbit

An artificial fruit (AF) was used to test for social learning in pig-tailed macaques (Macaca nemestrina) and adult humans (Homo sapiens). A monkey demonstrator opened the AF, showing alternative methods to 2 groups of cage mates. Video films of the monkey demonstrations were presented to adult humans. Compared with chimpanzees and children, the macaques watched the demonstrations significantly less and in a much more sporadic manner. They also produced only very weak and transitory evidence of social learning. In contrast, the adult humans performed as one might expect of optimum imitators, even producing evidence of components of a 'ratchet effect.' Keywords: adult humans, artificial fruit, imitation, Macaca nemestrina, social learning

The relationship between the central nervous system neurotransmitter serotonin (5-HT) and behavioral responses and social inhibition to a novel conspecific social scenario in marmosets is investigated. Results establish that monoamine serotonergic influences play a role in behavioral response in marmosets, since naturally low and pharmacologically altered peripheral 5-HT leads to decreased behavioral inhibition.

Bed-building and use in 73 captive adult chimpanzees (Pan troglodytes) were tested experimentally and it was found that the wild-born subjects built and used beds significantly more often than the captive-born subjects. Captive-born chimpanzees raised through the juvenile period by wild-born mothers in a social setting as opposed to those raised by human caretakers in a nursery setting, would likely have had increased opportunities to observe bed-building.

A study was conducted to determine how capuchins reacted to inequitable rewards in an unrestricted cooperative paradigm, and which reward they would receive for their participation. It was observed that equity of the reward distribution did not affect success or pulling behavior, but the behavior of the partner in an unequal situation - such as who received higher-value food - affected overall success rates, and the ability to equitably distribute rewards had profound implications for activities such as group hunts.

Group-living animals are often faced with choosing between one or more alternative resource sites. A central question in such collective decision making includes determining which individuals induce the decision and when. This experimental and theoretical study of shelter selection by cockroach groups demonstrates that choices can emerge through nonlinear interaction dynamics between equal individuals without perfect knowledge or leadership. We identify a simple mechanism whereby a decision is taken on the move with limited information and signaling and without comparison of available opportunities. This mechanism leads to optimal mean benefit for group individuals. Our model points to a generic self-organized collective decision-making process independent of animal species. collective behavior | nonlinear dynamics | self organization

A study is conducted to demonstrate that both native and introduced populations of the Argentine ant are organized in supercolonies having effectively unrelated individuals. The increase in supercolony size decreased interspecific competition and makes the Argentine ant an even more formidable competitor in introduced habitats.

Some observations of social behavior of two aging female orangutans with a younger male son of one were made in an outdoor and in an indoor enclosure during the day. These included social distance, grooming, and locomotion plus wrestling and genital stimulation. As noted 15 years earlier, the two old females were never in contact with each other. Each showed contact and noncontact with the younger male. No clear social relation between the females was evident. Careful study of aging zoo populations could be useful.

Many studies have examined coexistence among similar small mammal species. Most investigations have tended to locus on interactions such as predation and competition, with less emphasis on use of habitat space, plant cover stratification, and food resource partitioning. We investigated 2 similar small mammal species, the white-footed mouse (Peromyscus leucopus) and the golden mouse (Ochrotomys nuttalli) to determine how differences in 3-dimensional habitat use, vegetative cover, and food resources allow for similar species to coexist. P. leucopus was removed from 4 of 8 experimental grids within a forested riparian peninsula to assess the effect of competitive removal on population dynamics of O. nuttalli. After removal of P. leucopus, the relative abundance of O. matalli in removal grids did not change significantly from abundance in control grids. However, differences in use of 3-dimensional habitat appeared to provide enough niche segregation to allow these 2 species to coexist in the same habitat. Abundant resources (acorn mast crop of Quercus nigra and heavy vegetative cover of Ligustrum sinense) also appeared to dampen competition between these 2 species. Key words: coexistence, community, competition, landscape, peninsula. Ochrotomys nuttalli, Peromyscus leucopus, 3-dimensional space

Animals adapted to extreme environmental conditions often show rhythmic activity with stable periodicity. We studied the daily activity pattern of European ground squirrels (Spermophilus citellus) to determine effects of environmental factors on this pattern. Activity was evaluated by counting the number of squirrels visible above ground in 3 manipulated groups. To test the hypothesis that midday air temperature contributes to the bimodal activity pattern, we manipulated ambient temperature perception by altering the coloration of their head fur. Significantly fewer dark-headed squirrels were visible on the surface in midday on sunny days than were light-headed animals. Because ambient temperature perception is strongly affected by the darkness of the top of the head. we concluded that extremely high midday ambient temperatures play a central role in contributing to the observed midday rest phase in ground squirrels. Key words: activity pattern, environmental effects, European ground squirrel, temperature perception

The attachment behaviour of extensively socialized (hand reared) dog, Canis familiaris and wolf, Canis lupus can be compared as puppies towards their human caregiver with that of pet dog puppies of the same age. It is conducted to find out whether dog puppies as young as 16 weeks show attachment to a human caregiver, extensive socialization by human caregivers affects attachment behaviour of dog puppies and evolutionary changes affect the emergence of dog human attachment.

The stingless bee, Trigona fulviventris can discriminate from non nestmates, then, bioassayed putative nestmate recognition cue compounds including fatty acids, alkanes, an alkene, wax esters and floral oils and at least one compound of every type affected nestmate recognition but sham treatment of controls has no effect on nestmate recognition. The implications of these findings are discussed for understanding the evolution of nestmate recognition in bees.

A study was conducted to investigate the strategies used by scrub jays to reduce cache theft by conspecifics and in three experiments scrub jays were allowed to cache wax worms in two different locations and some items were cached in nonpreferred sites. It was advantageous not to hide all the caches in one place since unpredictability might provide the best insurance against pilfering.

A study on the comparison on task performance and social interactions during nest construction in forced associations of the solitary halictine bee, Lasioglossum (Ctenonomia) NDA-1 and of the communal Lasioglossum (Chilalictus) hemichalceum was performed. The study revealed that in communal bees division of labour can be primarily explained by differences in task propensity and in solitary bees both behavioural asymmetry and social interactions contribute to division of labour.

A study on garter snakes, Thamnophis sirtalis who forcibly copulate with female snakes by inducing hypoxic stress in females was performed. The study revealed that the males target females emerging from their 8-month winter inactivity as they are weak and slow to resist and by courting females under conditions that maximize the males physical advantage.

A study aims on mate-guarding and paternity in mandrills, Mandrillus sphinx to examine cycle day and selection by males to investigate factors influencing the ability of alpha males to monopolize females. The results revealed that the males mate-guarded on periovulatory days more than on other receptive days and during conceptive cycles more than during nonconceptive cycles.

A study on whether shiny cowbirds Molothrus bonariensis can improve the acquisition of a feeding response by observing a demonstrator or their own species with which they share roosts and foraging flocks was conducted. The studies revealed that shiny cowbirds could acquire behavioural by observing other individuals and learn from heterospecifics, which they share roosts and foraging flocks as readily as they do from conspecifics.

The wild-type zebra fish (Danio rerio) was presented with two artificially selected Danio rerio strains with reduced stripe expression as well as the stripeless Danio albolineatus and the striped Danio nigrofasciatus with simultaneous choices between synthetic, computer-animated shoals of stripeless and striped Danio. Each species and strain of Danio preferred the phenotypes that most resembled its own with a strong preference for striped stimuli by fish with dark-stripe phenotype, and strong preference for no stripes by fish lacking stripes.

Large phenotypic differences are often observed between individuals in large variation in abiotic conditions between measurements, in behavioral and evolutionary ecology studies. The inclusion of covariates in statistical analyses has proved to control nonrandom differences between individual data point in these studies.

Studies found that levels of extrapair paternity in splendid fairy-wren broods predicted by genetic similarity between social mates. The results suggested that female splendid fairy-wrens might indirectly benefit from extrapair mating since it led to lower levels of inbreeding and increased heterozygosity in their offspring.

The delayed-response problem is used to investigate the temporal characteristics of the ability of animals to represent and remember objects that have disappeared. The findings reveal that domestic chicks have striking abilities to remember the location of biologically attractive objects but outperform most mammals, including primates.

The fitness of 33 Bombus terrestris colonies resulting from 188 brother-sister matings is compared to that of 43 outbreed colonies. As a population, B. terrestris is likely to cope with inbreeding episodes, however, among-family variation in the effects of inbreeding intensifies the differential representation of families in the population.

A new theoretical analysis of individual differences and cross- situational consistency of behavior is proposed. The authors hypothesized that the social behavior of mice (Mus musculus) is determined by individual differences among animals in behavior emitted (i.e., actor effects), in behavior elicited from social partners (partner effects), and by unique responses of one animal to another (relationship effects). Each effect represents a distinct facet of individual differences with different psychological meaning: likewise, the cross-situational consistency of each effect has a distinct psychological meaning. Individual differences in behavior emitted were observed, and these actor effects were consistent longitudinally. Individual differences in behavior elicited from social partners were observed, and these partner effects were also consistent longitudinally. Unique responses to specific social partners also determined behavior but were inconsistent longitudinally. The theoretical importance of reconceptualizing the concepts of individual differences and cross-situational consistency in behavior is discussed. Keywords: individual differences, cross-situational consistency, dyadic behavior, social relations model, Mus musculus

The interindividual differences in mean fecal glucocorticoid levels among males in three groups of wild ring-tailed lemurs to better understand the physiological costs of group living for males in a female-dominant species that exhibits strict reproductive seasonality are examined. Marked male-male mating competition did not result in a greater stress response for adult male ring-tailed lemurs at Beza Mahafaly Reserve.

The hypothesis that wild golden lion tamarin female, whose social structure is characterized by low aggression and high social support, would not show rank-related differences in glucocorticoids but would show reproductive changes. The results show that the lack of differences in cortisol excretion between dominants and sub-ordinates is likely due to the low levels of overt aggression and the high level of social support available to subordinate females.

Female mice discriminate between uninfected males and infected males with parasites such as intestinal nematode Heligmosomoides polygyrus, on the basis of social cues, displaying aversive responses to the odors of infected males. Female mice whose gene for the neuropeptide, oxytocin (OT) is deleted, is used, to show that at least one normal allele for OT is required for the discrimination, individual recognition, and avoidance of Heligmosomoides polygyrus males on the basis of color.

An aspect of the social-bonding hypothesis, which proposes that social play strengthens long-term bonds between individuals, enhancing future alliances is evaluated. Results reveal that the strengthening of long-term bonds between potential dispersal partners is not the function of social play in meerkats.

The social cohesion hypothesis of play asserts that the adaptive function of social play is to strengthen affiliative ties between group members thereby increasing cohesion within the social group. However, a study revealed that the behavior of young meerkats failed to fulfil this hypothesis and concluded that social play is unlikely to have the capacity to promote social cohesion in mammals.

The transfer of social information through chemical and mechanical signals during agonistic encounters by the crayfish, Orconectes rusticus is examined. Results reveal that a correlation of urine releases with current generation and agonists behaviors appears to be an indicators for eventual dominant-subordinate relationships.

Animals commonly modify their behavior in the presence of a conspecific or in response to signals. This is particularly true in the context of aggressive exchanges, which animals use to form networks of social relationships and to communicate social status associated with those relationships. Although hierarchical structures are a widespread phenomenon that has been studied extensively, the dynamic communication processes, specifically chemical communication in this review, is relatively overlooked. In particular, it is the exchange of information during agonistic interactions that mediates hierarchies and/or alters the outcomes of agonistic interactions. Given the theoretical appeal of these interactions, and the evolutionary importance and taxonomic diversity associated with social hierarchies, it is not surprising that the sensory mechanisms involved in the formation and maintenance of hierarchical structures have received recent attention. In crayfish, dominance is thought to be largely determined by physical superiority, where encounters are largely dyadic and fighting behavior is highly stereotyped. However, recent evidence has shown that the outcome of dyadic encounters are dependent upon a number of factors other than physical size, that include the exchange of chemical information during encounters, previous social history, and the intrinsic neurochemical state of opponents. We have attempted to provide a comprehensive analysis of the extrinsic chemical processes (previous history, sensory communication, etc.) and intrinsic chemical processes (neurochemical state) that produce and maintain dominance relations and social hierarchies in crayfish. We hope that this review will bring together a global picture of the processes that determine a crayfish's social standing and how intrinsic and extrinsic chemicals have substantial effects on aggressive states and agonistic bouts.

A test was conducted to see whether the females actively change their schooling behavior with conspecifics according to the presence of a harassing male. It was seen that the female schooling behavior was a flexible strategy and social aggregation in poecitiids was an important factor influenced by the male sexual harassment.

The ability of 6-week-old female pigs to discriminate between pairs of female conspecifics in a Y-maze is investigated. It is seen that the pigs, which were rewarded after each correct choice, learned faster than the pigs, which were rewarded after each incorrect choice.

The temporal development and sensory basis of social discrimination by young chicks was investigated by conducting a series of experiments. It was concluded that the rapid development of individual discrimination by chicks was more influenced by the social partners' visual phenotype and not by the familiarization of smell and sedation.

Study was conducted to examine whether exposure to social odours, in the absence of other sensory contact with a 'slender' crayfish, alters subsequent agonistic behavior in crayfish. The results show that the 'senders' did not have sufficient chemical reserves to reinforce the visual display, while the 'receivers' had sufficient chemical reserves.

Observations on mate-searching female California fiddler crabs, showed that these crabs conducted much longer searchers than have been reported for other animals. The size of the holes of the burrows on incubation explained the reason for the sampling of many male burrows when searching for a mate by the females.