Divergence of odorant signals within and between the two European subspecies of the house mouse

The olfactory acuity of mice allows them to discriminate odorsof conspecifics differing by a few genes. This acuity is usedin habituation procedures where investigation of novel odorsby the mouse can be translated into relative difference or similaritybetween the stimuli. This study adapts these behavioral proceduresto address suprapopulation divergence among urinary odors inthe house mouse. Specifically, we investigate geographical patternsof odor divergence within and between 2 subspecies of the housemouse, Mus musculus musculus and Mus musculus domesticus, whichdiverged in allopatry and met secondarily in Europe where theyhybridize. Based on M. m. musculus perception, our study suggeststhat odors of the 2 subspecies differ in both allopatric andcontact zone populations and that divergence is more markedin the latter. Our earlier studies documented mate preferenceand signal divergence between the 2 subspecies. Hence, we considerthe role of the urinary odors as mating signals. We discusshow signal divergence between the 2 subspecies may relate toreproductive character displacement. This study validates theuse of habituation procedures to reconstruct geographical patternsof odorant signal divergence, providing a strong methodologicalplatform to address reproductive character displacement affectingcryptic mating signals in mammals.     

Habituation of medaka (Oryzias latipes) demonstrated by open-field testing

Habituation to novel environments is frequently studied to analyze cognitive phenotypes in animals, and an open-field test is generally conducted to investigate the changes that occur in animals during habituation. The test has not been used in behavioral studies of medaka (Oryzias latipes), which is recently being used in behavioral research. Therefore, we examined the open-field behavior of medaka on the basis of temporal changes in 2 conventional indexes of locomotion and position. The findings of our study clearly showed that medaka changed its behavior through multiple temporal phases as it became more familiar with new surroundings; this finding is consistent with those of other ethological studies in animals. During repeated open-field testing on 2 consecutive days, we observed that horizontal locomotion on the second day was less than that on the first day, which suggested that habituation is retained in fish for days. This temporal habituation was critically affected by water factors or visual cues of the tank, thereby suggesting that fish have spatial memory of their surroundings. Thus, the data from this study will afford useful fundamental information for behavioral phenotyping of medaka and for elucidating cognitive phenotypes in animals.     

Parasite-induced change in host behavior of a freshwater snail: parasitic manipulation or byproduct of infection?

Host behavioral changes due to parasitism are often assumedto be adaptations of the parasite. However, behavioral effectsof parasites may be a generalized response to parasitism andonly coincidentally beneficial for parasite transmission. Forthis reason, alternatives to the manipulation hypothesis shouldbe tested. Previous work demonstrated that the trematode parasiteMicrophallus sp. influences the behavior of the snail Potamopyrgusantipodarum in a way that may increase the probability of transmission.Here I report work conducted to test alternatives to the manipulationhypothesis. In a field study, the effect of Microphallus onbehavior was compared to that of two other castrating parasitegroups to determine if the behavioral change is simply a byproductof parasitism. Also, the foraging behaviors of infected anduninfected snails were examined in the presence and absenceof food resources to determine if the hunger level of Microphallus-infectedsnails could account for the parasite-induced behavioral change.First, Microphallus-infected snails were found on top of rocksduring the day less often than the two other parasite groups. Thisevidence suggests that the behavioral change caused by Microphallusis specific to Microphallus-infected snails. Second, Microphallus-infectedsnails responded to the lack of food differently from uninfectedsnails. Uninfected snails retreated to safer positions underrocks when the food source was removed from the top of the rocks,while Microphallus-infected snails remained on top of the rockswhere the risk of consumption by the final host is greater.Taken together with previous studies, these results suggestthat infection by Microphallus results in behavior that enhancesparasite transmission.     

Annelid Endocrine Disruptors and a Survey of Invertebrate FMRFamide-Related Peptides

There is a growing body of literature describing the actionsof endocrine disruptors on annelids. These pollutants causedecreases in growth and reproductive output, delay sexual maturation,and inhibit the immune system in annelids. More studies areneeded to determine the mechanisms that underlie these responses.Most invertebrate endocrine disruptor research focuses on steroids.In recent years many new invertebrate peptide hormones includingthose related to the molluscan peptide FMRFamide have been identified.Since the storage of these peptides can be inhibited by steroidsduring insect metamorphosis, they may be affected by endocrinedisruptors. Therefore, it is worthwhile to give a brief overviewof this peptide family to those studying endocrine disruptionin invertebrates with the hope that they may begin to considerthese peptides in their future research. In 1977 Price and Greenbergisolated FMRFamide from the cerebral ganglia of the clam, Macrocallistanimbosa. Since then researchers have used bioassays and immunoassaysto identify a large number of FMRFamide-related peptides (FaRPs)from many invertebrate phyla. Even more peptides are predictedby the FaRP genes that have been sequenced. FaRPs have a varietyof functions and act as neurotransmitters, neuromodulators,or neurohormones. Each function is species and tissue specific.Most FaRP receptors are linked to a second messenger system.However, at least one is a ligand gated sodium channel. On goingstudies are examining FaRPs from the molecular to organismallevel.     

Behavioral olfactory discrimination of mixtures in the spiny lobster (Panulirus argus) based on a habituation paradigm

A habituation paradigm was used to examine behavioral aspectsof discrimination of stimulus quality in olfaction in the spinylobster (Panulirus argus). Magnitude of search response to twoconcentrations of artificial mixtures of crab, oyster, mulletand shrimp and to artificial seawater was measured in five lobstersbefore and immediately after habituation to crab mixture. Habituationto crab mixture was accomplished through 2-min presentationsof 5 ml of alternating concentrations (0.05 and 0.5 mM) of crabmixture stimulus, repeated every 5 min for a total durationof at least 3 h. This procedure resulted in at least a 42% decreasein response to any mixture, but the decrease was greatest forcrab mixture, the habituating stimulus. A habituation index,measured as post-habituation response relative to pre-habituationresponse, was used to evaluate discrimination between crab andeach of the other three mixtures. The habituation index wassignificantly greater for crab (90%) than for oyster (49%) andfor mullet (47%) mixtures. The habituation index for shrimpmixture (65%) was intermediate to these three mixtures. Thus,shrimp mixture is perceived by lobsters as being more similarto crab mixture than is either oyster or mullet mixture. Thesepatterns of discrimination parallel those reported for associativelyconditioned lobsters (Fine-Levy et al., 1987, 1988) and fora population of olfactory receptor cells (Girardot and Derby,1988).     

On the Validity of a Single (Boldness) Assay in Personality Research

A common method to assess behavioral types in personality research involves the use of a single emergence test (employed by researchers working on fish, avian, mammal, amphibian, and invertebrate taxa), whereby a shorter latency to emerge from a holding container into a novel environment is inferred to represent greater ‘boldness’. Although any behavior might be context specific, studies using this single assay type must assume it reflects boldness in other similar contexts, otherwise it cannot reflect personality (defined as consistency across time and/or contexts). We attempted to validate whether a single assay of this type is correlated with other similar assays of boldness under more familiar, and less stressful, situations. We compared single emergence test scores of two species of damselfish (Pomacentrus wardi; P. amboinensis) in a novel environment, with two different behavioral assays of the same fish in subsequent repeated trials in home tanks. Although behavior was highly repeatable in home tanks, we found no correlation between emergence test scores in the novel environment and measures of latency to emerge from shelter following disturbance, or activity levels, on the first, second, or third observations in home tanks; there was also no correlation when we used average home tank scores from mixed models that accounted for individual differences (i.e., plasticity) in the rate of habituation (latency) and acclimation (activity). Our results therefore lead us to question the validity of using this single emergence test assay as a predictor of general boldness and to question the use of any single assay of behavior in personality research.     

截头堆砂白蚁研究概况

截头堆砂白蚁Cryptotermes domestictis是世界性蛀木害虫, 也是我国主要危害木材的白蚁之一。本文重点综述了我国截头堆砂白蚁补充型繁殖蚁的形成、生存、繁殖和扩散, 以及成熟群体的分飞, 原始繁殖蚁的形成周期和行为特点, 初建群体的形成、发展发育和取食行为的生物学和生态学研究进展。并且对该种白蚁的控制进行了探讨, 为控制该种白蚁的扩散、传播和为害提供理论依据。     

Yolk testosterone modulates persistence of neophobic responses in adult zebra finches, Taeniopygia guttata

Individual differences in animal behavior can be attributed to genetic as well as non-genetic influences. One mechanism by which the behavioral phenotype of an individual can be shaped is via transmission of maternal sex steroids. In this study, we examined the role of yolk testosterone (T) in controlling neophobia in 9-month-old, sexually mature zebra finches (Taeniopygia guttata). Offspring hatched from either T-treated or control eggs were subjected to a sequential series of behavioral tests in which we measured the neophobic response and its persistence towards two unfamiliar stimuli. Birds from T-treated and control eggs did not differ in their latencies to approach and eat a novel food source during their first encounter. However, egg treatment affected subsequent habituation. Latencies decreased in both groups over a habituation period of 5 days, but considerably more so in T-offspring. Although males appeared to approach novel food faster than females, there was no overall sex effect during the habituation period. When a novel object was added in combination with the previously learned food stimulus, this caused an behavioral shift in approach latencies. In males, control offspring had significantly shorter latencies than T-offspring, whereas there was no difference among females. The latency to eat in the same test was not significantly affected by sex or egg treatment. Our results demonstrate long-term effects of prenatal T on neophobic responses in adult zebra finches. We hypothesize that prenatal T may be one underlying mechanism for individual differences routine formation.     

Seismic Signal Use by Fossorial Mammals

The subterranean environment is not favorable for the use ofvision or the audition of airborne sounds as means of long-distancesensory perception. However, seismic vibrations have been shownto propagate at least an order of magnitude better than airbornesound between the burrow systems of the mole-rat Georychus capensis.The use of the seismic channel for communication undergroundis well documented for other species of bathyergids, as wellas the spalacine mole-rat Nannospalax. It has recently beensuggested that the golden mole Eremitalpa granti namibensismay also be sensitive to ground vibrations, in this case usedin foraging in its desert habitat. In this paper, the use of seismic signals among these and otherfossorial mammals is reviewed from theoretical, behavioral andanatomical standpoints. The question of whether auditory orsomatosensory means are used to detect vibratory signals isexamined. Attempts to explain the distribution of seismic sensitivityand communication mechanisms among fossorial mammals are considered.The potential influences of different soil type and diggingmethods are discussed, and it is proposed that digging mechanismsinvolving the head might preadapt a fossorial mammal towardsthe development of seismic sensitivity.     

Phagocytosis as a Biomarker of Immunotoxicity in Wildlife Species Exposed to Environmental Xenobiotics

In the present paper, we are reviewing experimental evidencedemonstrating that phagocytic cells, such as macrophages, maybe used as a biomarker of immunotoxicity in wildlife studies.We will first present data obtained after exposure in vitrowith selected chemicals showing the comparative sensitivityof phagocytic cells from different species. These results demonstratethat, at least for metals, each species produce a similar shapeddose-response curve, although considerate interspecies sensitivityis evident. These results also demonstrate the sensitivity ofthe phagocytic activity, suggesting indeed that this functioncould be used to monitor exposure to chemicals. The similarshaped dose-response curves imply that mechanisms of actionmay also be similar. Furthermore, based on the relative speicessensitivity, sentinel species could be selected for field monitoring.Such an approach may also be useful to establish correctionfactors required to extrapolate results between species. Thissensitivity of the phagocytic activity of macrophages will befurther under controlled conditions in laboratory animal models.Finally, the reliability of this approach will be demonstratedusing case studies with wildlife species.     

Interspecific differences in differentiation and dedifferentiation patterns in the genusNicotiana

Differentiation on hormoneless media, habituation ability and crown gall induction inNicotiana tissue cultures have been used as physiological parameters of evolutionary differentiation between species. Some of them on hormone free media differentiated whole plantlets, others produced only shoots or roots or showed undifferentiated growth (habituation), some eventually died. Moreover, the same genotypes showed a differential behaviour as far as tumor formation byAgrobacterium tumefaciens was concerned. Particularly, the competence for crown gall transformation inNicotiana species seems negatively correlated with differentiation capacity and may be ascribed to differences in the plants capacity to synthesize growth regulators. The correlation between the results obtained and the phylogenetic position of the genotypes tested is finally discussed.     

Endocrine Correlates of Seasonal Body Mass Dynamics in the Collared Lemming (Dicrostonyx groenlandicus)

Many winter-active temperate rodent species show seasonal, photoperiod-mediatedchanges in body mass that correlate with changes in food availability,gaining mass when food is abundant. The collared lemming (Dicrostonyxgroenlandicus), an arctic species, also undergoes a seasonaltransition in body mass, but one that is temporally out of phasewith that observed in species from lower latitudes; whereastemperate species increase in mass when exposed to relativelylong day lengths, collared lemmings do so under long but decreasingday lengths. This adaptation may be in response tothe timingof peak above-ground biomass in the arctic. Validation of thishypothesis requires a more thorough examination of both collaredlemmings and other arctic species. In the collared lemming, photoperiod-mediated changes in bodymass are correlated with changes in serum concentrations ofprolactin, thyroid hormones, corticosterone, and growth hormone,and pineal concentrations of melatonin. These observations arecompared to those obtained with temperate small mammals, andpossible cause-and-effect relationships between body mass andhormonal parameters are discussed.     

Effects of Photoperiod on the Apparent Viscosity of Leaf Cytoplasm in Kalanchoe blossfeldiana: 2. Some Long- and Short-term Effects of Daylength and Spectral Composition of Light

The effects of a range of daylength treatments upon the apparentviscosity of the mesophyll cytoplasm were tested in Kalanchoeand some other daylength-sensitive species by means of a centrifugationtechnique. In Kalanchoe, apparent viscosity increases with increasingshort-day induction, the rise being rapid initially but fallingoff subsequently in the same way as the flowering response.Since the response to light-break treatment is equivalent tolong-day conditions, the effect is truly photoperiodic. Theshort-day increase appears to be only partially reversible uponreturn to long-days. Single leaves may be treated and the effect is not translocatedto the opposite member of a leaf pair. The immediate response to change from light to dark and viceversa is oscillatory; e.g. in the dark an initial fall is succeededby a steep rise and then a more gradual fall in apparent viscosity. Light-breaks with red light are equivalent to white light, andthose with far-red light to darkness. No reversal of red effectsby far-red light has yet been demonstrated. In other species tested, apparent viscosity was significantlyhigher under short-day in Chrysanthemum and Michaelmas Daisy,and under continuous light in Epilobium, i.e. in the daylengthswhich induce flowering. The results are discussed in relationto the present theories of photoperiodism.     

Morphological and behavioral defenses in dragonfly larvae: trait compensation and cospecialization

Many animals have two basic traits for avoiding being killedby a predator: behavioral modification and morphological defense.We examined the relationship between antipredator behavior andmorphological defense in larvae of three closely related dragonflyspecies within the genus Leucorrhinia. The three species differwith regard to their morphological defense as expressed in thelength of the larval abdominal spines. Results showed that longerabdominal spines provided protection against an attacking fishpredator (perch) because the probability of being rejected afteran attack was significantly higher in the species with the longestabdominal spines. In contrast to other studies, the specieswith the strongest morphological defense did not show the leastbehavioral predator avoidance. Instead, the species with intermediatemorphological defense showed the least predator behavioral avoidance.The results suggest that the Leucorrhinia system is a mixtureof trait cospecialization (a positive correlation between antipredatorbehavior and morphological defense) and trait compensation (anegative correlation between antipredator behavior and morphologicaldefense). Differences in the relationship between morphologicaland behavioral defense between species might be related to abundancepatterns of the three species in lakes with and without fishpredators.     

Habituation to a danger stimulus in two semiterrestrial crabs: ontogenic,ecological and opioid modulation correlates

Previous research on the habituation of the crab Chasmagnathus granulatus to an iterated visual danger stimulus disclosed two remarkable features of this mnemonic process: a) the ready acquisition and long-lasting nature of the habituated response, and b) the likely endogenous opioid modulation of the shortterm habituation, whose potential adaptive value was studied here. Both the habituation ability and the opioid modulation of such ability were analysed in Chasmagnathus granulatus and Pachygrapsus marmoratus, two closely related grapsid species that diverge widely in ecology. Results indicate that Chasmagnathus has a much greater capacity to habituate than Pachygrapsus, showing a more pronounced short-term habituation which seems to some extent mediated by an endogenous opioid mechanism, and a faster acquisition of a greater longterm habituation partially mediated by memorial representation of the contextual cues. A correlation between these differences and those related with the ecological pressure was discussed. The capacity of acquiring longterm habituation in crabs of the same species but different age was also assessed, showing that old animals clearly exhibit lower retention of the habituated response than young crabs. The possible correlation between this age-dependent change and an ontogenetic shift of habitat was discussed.     

Multiple Character Analysis of Canis lupus, latrans, and familiaris, With a Discussion of the Relationships of Canis niger

A multiple character analysis was undertaken of a broadly representativesample of three species:Canis lupus (wolf), C. latrans (coyote),and C. familiaris (dog). These species are clearly and significantlydistinguished by the technique of linear discrimination. Theanalysis provides a basis for the identification of skulls notobviously distinguishable by size or other diagnostic characters. Early populations of Canis n. niger and C. n. gregoryi (redwolf) are compared with the three species above and are foundto form a cluster with lupus and to be sharply distinct fromthe other two species. Additional comparisons show that whilelupus lycaon and niger both overlap with lupus, they are distinctfrom each other. This entire cluster is quite distinct fromlatrans, with niger being the farthest removed. A sample populationof C. n. gregoiyi, from the edge of the extending range of C.latrans, was examined and found to show too great a range ofvariation to be attributed to a single species.     

Omnivory in cyclopoid copepods: comparisons of algae and invertebrates as food for three, differenfly sized species

We examined the importance of algal versus invertebrate preyfor three cyclopoid copepods by comparing reproductive successfor females fed on three diets: exclusively algal food, exclusivelyinvertebrate prey and a combination of algal plus invertebrateprey. The three cyclopoid species represent a distinct gradientin body size: Tropocyclops prasinus mexicanus (small body size),Diacyclops thomasi (medium body size) and Mesocyclops edax (largebody size). Our results provide strong evidence for the potentialimportance of algae in the diet of adult cyclopoid copepods.However, the role of herbivory is dependent on species bodysize. We found that algae are the key dietary factor for reproductivesuccess of the small T.p.mexicanus. In contrast, the availabilityof invertebrate prey had a greater influence on reproductionby the two larger species. Overall, cyclopoid copepods shouldbe generally considered as having the potential to derive theirenergy from either animal or algal sources. This has importantconsequences for interpretations of the forces influencing zooplanktoncommunity diversity as well as for general food web theory.     

Invertebrate predation selects for the loss of a morphological antipredator trait

Antagonistic selection by different predators has been suggested to underlie variation in morphological antipredator traits among and within species. Direct empirical proof is equivocal, however, given the potential interrelationships of morphological and behavioral traits. Here, we tested whether spines in larvae of the dragonfly Leucorrhinia caudalis, which are selected for by fish predators, are selected against by invertebrate aeshnid predators. Using a manipulative approach by cutting spines instead of making comparisons among species or inducing spines, we were able to decouple the presence of spines from other potentially covarying morphological antipredator traits. Results showed survival selection for the loss of spines imposed by invertebrate predation. Moreover, spined and nonspined larval L. caudalis did not differ in the key antipredator behaviors, activity level, and escape burst swimming speed. The observed higher mortality of spined larvae can therefore be directly linked to selection by aeshnid predation against spines.     

Copepod reaction to odor stimuli influenced by cestode infection

The cestode Schistocephalus solidus uses copepods as first andsticklebacks as second intermediate hosts. For transmission,an infected copepod has to be preyed upon by a stickleback.We used copepods of the species Macrocy albidus to test whetherinfected and uninfected copepods differ in their reaction totwo kind of simultaneously presented odors: odors of sticklebacksand odors of sticklebacks and conspecificz. By giving this choice,we attempted to force the copepods to make a trade-off betweenthe benefit of risk dilution and possible predator confusionand the costs of food competition and other disadvantages inducedby conspecifics. Within 1–8 h after last feeding, uninfectedcopepods clearly preferred the odors of conspeciflcs under thechemically simulated threat of predation. This was in contrastto the infected copepods, who tended to avoid the odor of conspecifics.When the time between experiment and last feeding varied, infectedcopepods showed an increas preference for fish water only (oravoided conspecthcs) with increasing hunger level This suggeststhat S. solidus benefits from hunger-induced behavioral changesof its copepod host by influencing its microhabitat selection.The same effect could be found in both sexes; however, it wassignificantly more pronounced in male than in female copepods.We propose several hypotheses that could explain the differencebetween the sexes in their infection-dependent microhabitatselection.