The response of a bumblebee goby,Brachygobius sabanus,to chemical stimuli from injured conspecifics

Synopsis Brachygobius sabanus move less often and spend less time swimming when they detect chemicals released from injured conspecifics. This resembles the alarm response found in ostariophysan fishes, darters, and at least one other gobiid. Chemicals from injured Poecilia reticulata do not induce an alarm response in B. sabanus.     

Threat calls in alliance formation by members of a captive group of Japanese monkeys

The vocal behavior of threat calls was investigated in a captive group of Japanese monkeys (Macaca fuscata fuscata). The vocalizations were heard most often when they undertook winner-support during triadic agonistic interactions. The likelihood of call emission in support of the winner was affected by the attributes of the participants, and not by the types of agonistic behavior. The calls were emitted by intermediate ranking animals frequently in support of high ranking animals and in support of females. The calling behavior of winner-supporters appears to advertise the partner and distant group members of their support for reciprocation in the near future.     

Alarm in a wasp-wasp nesting association: Do members signal cross-specifically?

Summary We studied interspecific alarm communication between two species of social wasps in a nesting association in northwestern Costa Rica by testing the alarm responses ofPolybia occidentalis andMischocyttarus immarginatus to venom of both species. This is the first investigation of alarm pheromone in the genusMischocyttarus. M. immarginatus did not respond with alarm behavior to the venom of either species.P. occidentalis, which responds to its own venom with alarm behavior (Jeanne, 1981), also responded with alarm behavior to the venom ofM. immarginatus, but with much less intensity. Since heterospecific venoms did not release species-typical levels of alarm behavior, we conclude that interspecific alarm signalling plays no role in the nesting association.     

Latency of cathepsin B secreted by human colon carcinoma cells is not linked to secretion of cystacin C and is relieved by neutrophil elastase

The lysosomal cystein proteinase cathepsin B is shown to be secreted by ten human colon carcinoma cell lines and to accumulate in culture media as a latent enzyme. The cell lines also secrete a physiological inhibitor of cathepsin B, cystatin C. A significant correlation was found between secretion of the latent enzyme and the inhibitor (r = 0.755, P < 0.01). The aim of the present study was to modulate the respective secretion of the two antagonists to test whether or not latency of cathepsin B was due to the concomitant secretion of the inhibitor. SW480 colon carcinoma cells were treated with the acidotropic agent ammonium chloride, phorbol 12-myristate 13-acetate, and the inflammatory cytokines TGF-β, TNF-α, and IL-1β. Ammonium chloride significantly increased latent cathepsin B levels without affecting the constitutive secretion of cystatin C. Phorbol 12-myristate 13-acetate induced a 4- to 5-fold increase in secreted latent cathepsin B, but did not alter significantly the accumulation of cystatin C in media. The cytokines, TGF-β, TNF-α, and IL-1β, had no major effect on the expression of these two antagonists. Latent cathepsin B released from human carcinoma cells could be efficiently activated by neutrophil elastate at neutral pH. It is concluded that latent cathepsin B is a true proenzyme rather than an enzyme-inhibitor comples. In addition, our data from neutrophil elastate activation experiments indicate that a proteolytic system for activation of the tumor cell-secreted latent enzyme may exist in vivo.     

Bioacoustic analysis of frog calls from northeast India

Mating calls of three frog species abundant in northeast IndiaRana tigerina,Rana cyanophlyctis andRana limnocharis were recorded in the fields of Assam and Meghalaya during their breeding season (July-August, 1991). The calls were analysed for their temporal and spectral characters. They were species specific, with distinct call duration and call period, number of pulses per call and interpulse interval, and dominant frequency and frequency domain. A comparison of the mating calls ofRana cyanophlyctis with those of the siblingRana ehrenbergi from Yemen showed differences in their temporal and spectral characters, supporting the suggestion that these two species are distinct species, rather than subspecies of the same species. Differences in the temporal and spectral pattern were found in the mating calls of morphologically alike specimens ofRana limnocharis, indicating that the present morphotypeRana limnocharis in northeast India is composed of several species.     

Differences in preference for species-specific female calls between acoustically experienced and acoustically naive maleRibautodelphax planthoppers (Homoptera: Delphacidae)

Males of the planthopper Ribautodelphax imitanswere exposed to playbacks of either conspecific or heterospecific (R. imitantoides)female calls during their development from egg to adult, and thereafter these, as well as naive males,were offered a two- way choice between these calls. Males of all treatments approached the conspecific call significantly more often. However, males primed by the conspecific call chose the heterospecific call almost four times less often than did males primed by heterospecific calls or naive males, thus showing that the preference for conspecific calls can be partly learned. Males primed by heterospecific calls performed very similarly to completely naive males, suggesting that the signal recognition mechanism is much less sensitive to heterospecific calls than to conspecific calls. Males with experience of the conspecific female call tended to take more time to reach the call source in the trials than both other types of males. The evolutionary implications of these findings are discussed.     

Breakup and re-formation of colony in the first-instar larvae of the winter cherry bug,Acanthocoris sordidus thunberg (Hemiptera: Coreidae), in relation to the defence against their enemies

The winter cherry bug, Acanthocoris sordidusThunberg , lives in aggregation especially in their early larval instars. Using the 1st-instar larvae of this species, the author tried to clarify both the processes and the mechanisms of the breakup and later re-formation of colony in relation to the defence against their enemies. The results obtained were summarized as follows.

1. In the field population, there is a high possibility of dispersal of the 1st-instar larvae from a colony possibly through the disturbance by some predators but they can re-form a colony with each other or join, with colonies of different instar larvae.
2. The individuals in a colony immediately disperse through the attack of predatory coccinellid beetle, Harmonica axyridis but tend to re-form a colony in a short time.
3. The breakup of colony is caused by the secretion from the attacked individual.
4. The formation of colony is attributed to the habit closely related with the senses of smell and/or contact.

From these results, it was concluded that the dispersal of 1st-instar larvae from a colony, followed by the re-formation of a colony, is an an adaptive behaviour to escape from the attack by their predators.     

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ABSTRACT

In most mammals, adults produce relatively low frequency vocalizations compared to those of juveniles. This rule is not maintained however at least in four species of ground squirrels, whose juveniles call at the adult's fundamental frequency. These findings have been obtained however with separate sets of juveniles and adults and no data is available concerning the ontogeny linked to these differences. Here we analyze the acoustic structure of alarm calls of the same Yellow Spermophilus fulvus and Speckled S. suslicus ground squirrel individuals, recorded as pups and as adults after hibernation. We found the fundamental frequencies of adults within the same frequency ranges as those of pups, in spite of the significant difference in body mass. In ground squirrels, severing the relationship between body size and call frequency removes some vocal cues to age. We discuss some functional hypotheses advanced to explain manipulations with fundamental frequencies in ground squirrels and other animals, and suggest the lack of data for discussing the mechanisms of such vocal tuning.     

Limited plasticity in the phenotypic variance‐covariance matrix for male advertisement calls in the black field cricket,Teleogryllus commodus

Phenotypic integration and plasticity are central to our understanding of how complex phenotypic traits evolve. Evolutionary change in complex quantitative traits can be predicted using the multivariate breeders’ equation, but such predictions are only accurate if the matrices involved are stable over evolutionary time. Recent study, however, suggests that these matrices are temporally plastic, spatially variable and themselves evolvable. The data available on phenotypic variance‐covariance matrix ( P ) stability are sparse, and largely focused on morphological traits. Here, we compared P for the structure of the complex sexual advertisement call of six divergent allopatric populations of the Australian black field cricket, Teleogryllus commodus. We measured a subset of calls from wild‐caught crickets from each of the populations and then a second subset after rearing crickets under common‐garden conditions for three generations. In a second experiment, crickets from each population were reared in the laboratory on high‐ and low‐nutrient diets and their calls recorded. In both experiments, we estimated P for call traits and used multiple methods to compare them statistically (Flury hierarchy, geometric subspace comparisons and random skewers). Despite considerable variation in means and variances of individual call traits, the structure of P was largely conserved among populations, across generations and between our rearing diets. Our finding that P remains largely stable, among populations and between environmental conditions, suggests that selection has preserved the structure of call traits in order that they can function as an integrated unit.     

Social monitoring via close calls in meerkats

Social monitoring of the actions of group members is thought to be a key development associated with group living. Humans constantly monitor the behaviour of others and respond to them in a flexible way depending on past interactions and the current social context. While other primates have also been reported to change their behaviour towards other group members flexibly based on the current state of their relationship, empirical evidence is typically linked to contextually specific events such as aggressive or reproductive interactions. In the cooperatively breeding meerkat (Suricata suricatta), we investigated whether subordinate females use frequently emitted, non-agonistic close calls to monitor the location of the dominant female and whether they subsequently adjust their response based on recent social interactions during conflict and non-conflict periods. Subjects discriminated between the close calls of the dominant female and control playbacks, responding by approaching the loudspeaker and displaying submissive behaviour only if they were currently threatened by eviction. Our results suggest that meerkats assess the risk for aggressive interactions with close associates depending on social circumstances, and respond accordingly. We argue that social monitoring based on non-agonistic cues is probably a common mechanism in group-living species that allows the adjustment of behaviour depending on variation in relationships.