Presence Of Chemical Cues Research Articles

Urinary chemical cues affect light avoidance behaviour in male laboratory mice,Mus musculus

Chemical signals from conspecifics can influence the behaviour and neuroendocrine axis of mice. Several different molecules are excreted with urine, depending on hormonal level, and can indicate the sex of the emitter. In male mice, these chemicals are the major urinary proteins (MUPs) and some small volatile odorant molecues that are found bound to them. We tested adult males for light avoidance behaviour in a two-chamber apparatus, with one light and one dark side, in the presence or absence of male urinary substances. The presence of chemical cues on either side of the cage was expected to modify light avoidance behaviour. The volatiles released from purified MUPs had the same effect as whole adult male urine, in that they induced a faster onset of exploration of the light compartment. The results show that mice can use the information carried by the odorant molecules released by MUPs to recognize the urine of male mice, and respond appropriately.

CHEMICAL SIGNALS IN MALE HOUSE MICE URINE: PROTEIN-BOUND MOLECULES MODULATE INTERACTIONS BETWEEN SEXES

AbstractThe role of urinary chemosignals in sexual interactions was investigated in pairs of adult mice. Based on previous findings, volatile molecules bound by the Major Urinary Proteins (MUPs) from adult male urine were thought to be sufficient to carry information about the sex of the emitter, and thus sufficient to modify the behaviour of conspecifics. In the first experiment, virgin and stud adult males were exposed to receptive females painted or not with MUPs-borne molecules. Both virgin and stud males showed an increased latency to the first anogenital sniff and a reduced number of sniffings towards MUPs-treated females. This suggests that adult mice are repelled by MUPs-borne volatile molecules, even in the presence of female stimuli conveyed by receptive mates. In the second experiment only stud males were tested, with ovariectomized or estrogen-primed females. These latter were either untreated, painted with MUPs-borne molecules or MUPs without volatile ligands. Ovariectomized females and those treated with MUPs without ligands received less sniffs than the other two groups. Estrogen-primed females were mounted more times, with a shorter latency. Ovariectomized females and females treated with MUPs-borne ligands were attacked earlier by males. The presence of chemical cues from male urine is thus sufficient to modify the behaviour of stud males towards receptive females. In particular, MUPs-borne volatiles are sufficient to act as male cues and to induce aggression towards receptive females. It can be speculated that in nature adult male mice rely on olfactory cues like MUPs-borne odorants to firstly identify a male conspecific and possibly use similar chemical cues from their own urine to signal their presence.

VISUAL ORIENTATION TO GASTROPOD SHELLS BY CHEMICALLY STIMULATED HERMIT CRABS, CLIBANARIUS VITTATUS (BOSC)

ABSTRACT Visually directed movements of the hermit crab Clibanarius vittatus (Bosc) toward 6 species of gastropod shells were studied in a circular arena with a white wall. The study tested the hypothesis that crabs visually discriminate between different species of shells. Only Investigating Crabs, those exhibiting chemically induced shell-investigation behavior, were tested. All trials were in the presence of chemical cues generated by freezing and thawing flesh from the gastropods Busycon carica or Polinices duplicatus. Directional orientation was absent when crabs were presented with the white background alone. Each shell was tested in different positions (e.g., anterior, posterior, upside-down, lateral). Crabs were attracted to shells in 9 of the 18 test conditions, with strongest attraction to Polinices duplicatus (posterior position) and Busycon contrarium (lateral position). Since attraction was not related to shell height, width, or surface area, it was concluded that crabs can discriminate between shells and were most attracted to shells that attain larger sizes. In a second experimental series, shells of B. contrarium or P. duplicatus were presented simultaneously in different positions. Crabs could distinguish between both species in different positions. When these 2 shell species were presented simultaneously, crabs were significantly attracted to P. duplicatus in the presence of the odor of either B. carica or P. dupticatus. Thus, these results support the hypothesis and further indicate that attraction to a shell involves a complex interaction of proprioreceptive input from the host shell, chemical cues indicating the availability of a new shell, and visual recognition of a particular shell species.

Stimuli Influencing the Release and Aim of Predatory Strikes of the Northern Pacific Rattlesnake (Crotalus viridis oreganus)

This study examined the relative importance of visual, chemical and thermal stimuli for releasing predatory strikes of the northern Pacific rattlesnake (Crotalus viridis oreganus). In experiment 1, adult snakes deprived of food for 30 days or longer were randomly presented four stimulus conditions (1 /day) combining visual, visual-chemical, visual-thermal and visual-chemical-thermal stimuli in moving models resembling mice. Experiment 2 replicated experiment 1 except that snakes were deprived of food 9 days and a fifth condition, live mice, was added. The number of strikes elicited by each condition suggested that visual cues alone were ineffective releasers of the strike, the addition of thermal cues dramatically increased the likelihood of attack, and the presence of chemical cues was not essential for striking. However, differences between the two experiments suggested that the contribution of chemoreception to prestrike behavior increased with prolonged food deprivation. The most effective strike-releasing conditions were struck more quickly and after fewer tongue flicks than less effective conditions, but tongue flick rates (recorded only in experiment 2) did not differ between conditions. Increased length of food deprivation appeared to decrease the latency to strike. Most models were struck in anterior regions, which suggested that directional movement contributed to the strike aim. The proportion of models envenomated during the strike differed between two model conditions, implying that rattlesnakes possess control over the mechanics of venom in-

Is Mating Different in Monogamous Species? The Midas Cichlid Fish as a Case Study

Monogamous species are typically sexually isomorphic, pair well before spawning is imminent, take much time to pair, are discerning about pairing, and appear to weigh multiple sources of information about species, sex, and quality of mate. The monogamous and polychromatic Midas cichlid ( Cichlasoma citrinellum ) distinguished between its own and a highly similar heterospecific behind a one-way mirror only when visual and chemical cues matched. Likewise, recognition of sex was hindered when interaction was precluded, even in the presence of chemical cues. Female choice of mate was most strongly influenced by the “normal, ” primitive, color and to a lesser degree by color of parents and siblings, making it difficult to account for positive color-assortative mating in the field. Females also selected the largest and the most aggressive males; size predicted a good defender of territory, and aggressiveness foretold effective protection of the young. Males, however, were not choosy. Pair formation features much aggression between the large male and smaller female, and gold-colored morphs (G) dominate normal (N) ones. That made it difficult for an N female to pair with a G male; using an N female the same size as the G male, however, resulted in the usual proportion of successful pairings. I propose three testable models of pair compatibility: complementarity, parity, and maximum male aggressiveness.

Ovipositional behavior of lesser peachtree borer in presence of host-plant volatiles

Reactions of lesser peachtree borer [Synanthedon pictipes (G&R)] to volatiles of peach wood, either natural or chemically fractionated, were observed. Mated females were stimulated by and responsive to such materials and deposited significantly more eggs on substrates, including unnatural hosts, that had been treated with aqueous mixtures of bark-canker materials. Stimulation to oviposit occurred even when the female was blinded, indicating the presence of chemical cues. Natural canker-bark extracts immediately stimulated ovipostion and for a few hours significantly increased the number of eggs laid. However, average fecundity was not increased. Antennectomy did not significantly decrease response to volatiles by gravid females, and alternate sites of such chemoreception were not located. Complex mixtures derived by solvent extraction, steam distillation, and volatiles trapping from bark, canker, and gum all had activity. Observations of insect behavior in outdoor cages and also in the laboratory indicated that visual, chemosensory, and mechanosensory receptors are involved in host finding and oviposition.

Effects of Chemical and Visual Stimuli upon Chemosensory Searching by Garter Snakes and Rattlesnakes

Many studies indicate that chemical cues activate garter snake feeding behavior whereas visual and/or thermal stimuli do so for rattlesnakes. However, no experiments have factorially combined chemical and visual cues for either of these taxa. The present work explored possible interactive effects of these stimuli on rate of tongue flicking (RTF) in garter snakes (Thamnophis radix haydeni) and rattlesnakes (Crotalus e. enyo, C. v. viridis, and Sistrurus catenatus tergeminus). In Experiments 1 and 2 snakes were exposed to four conditions represent- ing an orthogonal combination of presence vs. absence of visual and chemical stimuli arising from prey. RTF was recorded for 5 min under each condition. Garter snakes exhibited a significant elevation in RTF in the presence of chemical cues whether or not visual cues were present. There was also an effect of visual cues but no interaction between visual and chemical cues. Rattlesnakes did not respond to chemical cues; these snakes showed only an effect of visual cues. In Experiment 3, rattlesnakes were again observed as above, with the exception that test sessions were of 10 min duration. Behavior during the first 5 min was identical to that seen in Experiment 2, but during min 6-10 the snakes responded more in the condition containing visual plus chemical cues than in any other condition. Visual stimuli alerted rattlesnakes to the presence of potential prey and gave rise to elevated RTF which subsequently allowed these predators to utilize chemical cues that happened to be available. Hence, garter snakes and rattlesnakes use both chemical and visual information but differ in the sequence in which these stimuli are used.