Measuring and quantifying dynamic visual signals in jumping spiders

Animals emit visual signals that involve simultaneous, sequential movements of appendages that unfold with varying dynamics in time and space. Algorithms have been recently reported (e.g. Peters et al. in Anim Behav 64:131–146, 2002) that enable quantitative characterization of movements as optical flow patterns. For decades, acoustical signals have been rendered by techniques that decompose sound into amplitude, time, and spectral components. Using an optic-flow algorithm we examined visual courtship behaviours of jumping spiders and depict their complex visual signals as “speed waveform”, “speed surface”, and “speed waterfall” plots analogous to acoustic waveforms, spectrograms, and waterfall plots, respectively. In addition, these “speed profiles” are compatible with analytical techniques developed for auditory analysis. Using examples from the jumping spider Habronattus pugillis we show that we can statistically differentiate displays of different “sky island” populations supporting previous work on diversification. We also examined visual displays from the jumping spider Habronattus dossenus and show that distinct seismic components of vibratory displays are produced concurrently with statistically distinct motion signals. Given that dynamic visual signals are common, from insects to birds to mammals, we propose that optical-flow algorithms and the analyses described here will be useful for many researchers.Damian O. Elias and Bruce R. Land contributed equallyAn erratum to this article can be found at     

Behavioural and electrophysiological responses by reproductive female Neogobius melanostomus to odours released by conspecific males

Behavioural and electrophysiological responses of reproductive and non‐reproductive female round gobies Neogobius melanostomus to water previously occupied by male round gobies (reproductive male water) were compared. Reproductive females spent more time than non‐reproductive females in a tank near the input of water conditioned from reproductive males. Also, reproductive females swam significantly faster than non‐reproductive females, suggesting that reproductive male odour may have activated spawning behaviour. Olfactory epithelial field potential measurement (electro‐olfactogram, EOG) showed that reproductive male water was a potent olfactory stimulus to reproductive females, but not to non‐reproductive females. Reproductive females responded significantly more than non‐reproductive females to solid‐phase (octadecylsilane) extracts of reproductive male water. Also, when these extracts were separated on reverse phase high performance liquid chromatography (HPLC), reproductive females showed noticeably greater responses than non‐reproductive females to the fractions that eluted between 30 and 40 min. The behavioural data support the hypothesis that reproductive male round gobies release compounds into the water that attract potential mates. The EOG data indicate that these compounds can be quantitatively extracted from the water and be partially purified by HPLC. The evidence is not sufficient to indicate whether or not the compounds are steroids. The relatively early elution time on HPLC, however, suggests that if these compounds are steroids, then it is more likely that they will be conjugated rather than free steroids.     

Domestic chicks' runway responses to video images of conspecifics

Because chickens are highly social animals, live conspecifics are often used to provide an incentive or goal in studies of gait, sociality or fear that require the bird to traverse a runway. However, the variable behaviour of the stimulus birds can influence the approach/avoidance responses of the test birds and thereby confound the results. Because chickens modify their behaviour readily and appropriately to a variety of video images, including social stimuli, we asked if video playback might represent easily controllable and standardized alternatives to live birds. Female ISA Brown chicks were housed in groups of eight and then exposed to a blank illuminated television for 10 min per day from 2 to 7 days of age. At 8 or 9 days of age they were placed individually in the start box of a 1.6 m long runway and we recorded their responses to a monitor displaying selected video images that was situated in the goal box at the opposite end of the runway. In Experiment 1 chicks approached a monitor playing the video image and soundtrack of feeding chicks significantly sooner than one of a goal box with the food dish and background noise. In Experiment 2, chicks were exposed to the same video of feeding conspecifics with or without the associated sounds or to a video of the goal box with or without the chick soundtrack. Both the videos of other chicks elicited faster approach than did those of the goal box and the sound and silent versions were equally attractive. Adding the soundtrack of feeding chicks to the goal-box video failed to increase its attractiveness. The present results suggest that chicks are attracted towards televised images of other chicks. They also indicate that the visual and auditory components of the video stimuli did not exert additive effects and that approach reflected attraction to the visual image. Collectively, our findings suggest that video playback of selected social stimuli, such as feeding conspecifics, could be a valuable tool in tests requiring voluntary locomotion along a predetermined path.     

Single-cell responses in the ectostriatum of the zebra finch

The responses of single cells to computer-generated spots, bars, gratings, and motion-in-depth stimuli were studied in the ectostriatum and the adjacent neostriatum of the zebra finch, Taeniopygia guttata. No differences in neuronal properties could be detected between ectostriatum and neostriatum. The receptive fields of ectostriatal neurons are large, often extending over the entire visual field of the contralateral eye, and have oddly defined borders. The centers of the receptive fields, located in the foveal region, generally yielded better responses than the periphery, and exhibited different subdivisions. Neurons responded selectively to moving bars, preferring those moving parallel to their longest axis. An SDO (sensitivity, direction, orientation) analysis of responses to sinusoidal gratings showed that all orientations were equally represented by ectostriatal neurons, while there was a slight preference for forward and upward movements. The neurons also showed preferences for gratings of a particular spatial frequency, and responded vigorously to stimuli moving towards the eye (looming). Our results indicate that the ectostriatum is involved in both detecting displacement of the surround and in stimulus identification. By comparison with results obtained in the extrastriate cortex of mammals, it is concluded that the homology of the ectostriatum with the extrastriate cortex of mammals, which was proposed on the basis of hodological findings, is supported by our study.Abbreviations Di index of directionality - HW HH half-width at half-height - PLLS posterolateral lateral suprasylvian cortex - PMLS posterior medial lateral suprasylvian area - PSTH poststimulus time histogram - SDO sensitivity, direction, orientation     

Female Maylandia zebra prefer victorious males

Females of a widespread species of the rock-dwelling haplochromine cichlids of Lake Malawi, Maylandia zebra, show preference for males that successfully evict intruding males from their territory. This behaviour, experimentally induced by the investigators in a laboratory setting, was also preferred over males that were not permitted to interact with any other individual.     

Behavioral and adrenocortical responses to mate separation and reunion in the zebra finch

The adaptive value of social affiliation has been well established. It is unclear, however, what endogenous mechanisms may mediate affiliative behavior. The Australian zebra finch (Taeniopygia guttata) breeds colonially and adults maintain lifelong pair bonds that may be disrupted in the wild due to high mortality rates. Many of its natural, social behaviors are maintained in laboratory conditions, making this species well suited for studying the mechanisms of affiliation. This study examines the behavioral and neuroendocrine responses to pair mate separation and reunion in zebra finches. We measured plasma corticosterone (CORT) and behavioral changes following separation from a pair bonded mate, and again upon reintroducing the mate or an opposite-sex cagemate. Plasma CORT concentrations were: (1). elevated during pair mate separation, even in the presence of other same-sex individuals, and (2). reduced to baseline upon reunion with the pair mate but not upon re-pairing with a new opposite-sex partner. These findings show that zebra finches exhibit hormonal responses to separation and reunion specifically with a bonded pair mate and not with other familiar conspecifics. In addition, alterations in behavior during separation and reunion are consistent with monogamous pair bond maintenance. This study presents evidence for adrenocortical involvement in avian pair bonding, and for hypothalamic-pituitary-adrenal activation in response to an ecologically relevant social stressor.     

Sociability and responses to video playbacks in adult male rhesus monkeys (Macaca mulatta)

Studies of several primate species have suggested the existence of a personality dimension typically labeled ‘Sociability,’ which reflects an animal’s tendency to interact with others. The hypothesis that Sociability is related to social skill was tested in the present study by exposing six high- and six low-Sociable adult male rhesus macaques to videotaped presentations of unfamiliar males displaying aggressive or affiliative behaviors. Low-Sociable animals displayed higher frequencies of yawn, lower activity and tended to have higher durations of watching during the presentations that displayed social signals, and significantly fewer lipsmacks to presentations that depicted no social behavior. In response to viewing threats, tooth-grinds, yawns, and lipsmacks, both low- and high-Sociable animals’ most frequent response was to gaze avert; low-Sociable animals, however, had nearly twice the latency to gaze avert than did high-Sociable animals. The low-Sociable animals’ greater tendency to ‘sit and stare’ during the videotaped playbacks suggests that low-Sociable animals have poorer social skills. The possible developmental origins of variation in Sociability, and the functional consequences of such variation for survival and reproduction are discussed.     

Behavioural responses of three linyphiid spiders to pitfall traps

The behaviour of three linyphiid spider species (Araneae: Linyhiidae) towards pitfall traps was investigated in an experimental arena. Capture efficiencies were low with a mean of between 16 and 57 traps being encountered before spiders were caught. Survival time, trap encounter rate, trap entry rate and reactions towards vegetation were all found to be species-specific. These behaviours are considered to affect differentially pitfall trap efficiency and may partially explain the lack of clear relationship between pitfall trap catch and density found in published studies.     

Behavioural responses of male ruffed grouse (Bonasa umbellus,L.) to playbacks of drumming displays

Birds use a variety of sounds in their courtship displays, but the majority of behavioural studies have focused on vocalizations. In contrast, little is known about how non‐vocal sounds, or sonations, are used, even though many avian species produce them. The ruffed grouse (Bonasa umbellus) is a useful species to examine non‐vocal sounds because they lack vocal components in their courtship and rely on a non‐vocal sound to attract mates and defend their territory. Their courtship display, known as “drumming,” is created by the wings, and the number of pulses and speed (pulse rate) varies significantly among males. Anecdotal evidence suggested that males can affect the drumming behaviour of neighbouring males in drumming “duels” in an analogous way to song contests. Here, we test whether males do respond to the playback of drumming sounds of an unfamiliar male. Using a portable speaker system, we played recordings of drumming displays to males that were actively drumming themselves. Throughout each playback, we recorded the drumming behaviour of target males so that we could assess whether drumming activity changes following a playback as well as whether males change the speed of their display. Overall, male grouse were equally likely to approach the speaker or continue drumming following a playback. For those males that continued drumming, their drumming pulse rate was significantly faster following playbacks, but they drummed less often. These results indicate that male ruffed grouse do respond to drumming sounds, but the specific response differs among males. Because the differential response was not related to colour phase or whether a male was drumming in proximity to other males, we suggest that the response of individuals likely varies with other traits, such as hormone levels or behavioural syndrome.     

Deep body and surface temperature responses to hot and cold environments in the zebra finch

Global warming increasingly challenges thermoregulation in endothermic animals, particularly in hot and dry environments where low water availability and high temperature increase the risk of hyperthermia. In birds, un-feathered body parts such as the head and bill work as ‘thermal windows’, because heat flux is higher compared to more insulated body regions. We studied how such structures were used in different thermal environments, and if heat flux properties change with time in a given temperature. We acclimated zebra finches (Taeniopygia guttata) to two different ambient temperatures, ‘cold’ (5 °C) and ‘hot’ (35 °C), and measured the response in core body temperature using a thermometer, and head surface temperature using thermal imaging. Birds in the hot treatment had 10.3 °C higher head temperature than those in the cold treatment. Thermal acclimation also resulted in heat storage in the hot group: core body temperature was 1.1 °C higher in the 35 °C group compared to the 5 °C group. Hence, the thermal gradient from core to shell was 9.03 °C smaller in the hot treatment. Dry heat transfer rate from the head was significantly lower in the hot compared to the cold treatment after four weeks of thermal acclimation. This reflects constraints on changes to peripheral circulation and maximum body temperature. Heat dissipation capacity from the head region increased with acclimation time in the hot treatment, perhaps because angiogenesis was required to reach peak heat transfer rate. We have shown that zebra finches meet high environmental temperature by heat storage, which saves water and energy, and by peripheral vasodilation in the head, which facilitates dry heat loss. These responses will not exclude the need for evaporative cooling, but will lessen the amount of energy expend on body temperature reduction in hot environments.     

Behavioural responses of different blackfly species to short-term oxygen depletion

Behavioural changes of four larval blackflies (Simulium noelleri, S. ornatum (complex), S. trifasciatum [syn. S. spinosum] and S. variegatum) to experimental reduction of dissolved oxygen were investigated with videotechniques. Since these species are characterised by different habitat preferences, they were expected to respond differently to oxygen depletion. During experiments lasting 120–140 min., dissolved oxygen (DO) was reduced to 0.3–0.6 mg/1 within the first hour and kept constant for another hour. Water velocity in the laboratory channel was 135 cm/s. Transparent plastic walls allowed video-recording of larval behavioural responses to oxygen depletion. Blackflies did not engage in undulative or other ventilation movements, and they did not increase locomotory activity, nor did they actively drift. Oxygen depletion mainly altered filter-feeding activity and non-locomotory movements (bending and sweeping). With decreasing DO concentrations larvae of all four species reduced and finally ceased filter-feeding. Non-locomotory movements first temporarily increased and then also ceased, except in S. variegatum, where these movements were immediately suspended. DO-threshold values for cessation of filter-feeding and movements, as well as mortality indicated S. variegatum to be the most sensitive species in respect to oxygen depletion, while S. noelleri seems to be the most tolerant among the four blackfly species tested here.     

Behavioural responses of fathead minnows to carbohydrates found in aquatic environments

Carbohydrates make up a significant portion of dissolved organic carbon in waterways. Apart from studies demonstrating that chondroitin causes avoidance behaviours in some fish species, no work has been done to determine how fish respond to carbohydrates commonly found in their environment. In this study fathead minnows (Pimephales promelas) were attracted to N-acetyl-d -glucosamine, avoided d -arabinose and had no response to either d -xylose or d -glucose using a behavioural assay. This study provides further evidence that carbohydrates may be important chemosensory cues for fish.     

Behavioural and sensory responses to some neem compounds by Pieris brassicae larvae

Abstract. The efficacy of a commercial product (Margosan-O) to inhibit feeding in Pieris brassicae L. (Lepidoptera: Pieridae) larvae was compared to that of three pure triterpenoids of botanical origin: azadirachtin and salannin (occurring in Melia azedurach ), and toosendanin (occurring in M. toosendan ). In dual-choice behaviour tests the order of antifeedant efficacy was: Margosan-O > toosendanin > salannin > azadirachtin. The ranking order of their capacity to stimulate the deterrent receptor located in the medial sensillum styloconicum appears to be: Margosan-O = toosendanin > salannin > azadirachtin. In addition to stimulating the medial deterrent cell, toosendanin inhibits the sugar receptor and the glucosinolate receptor, both located in the lateral sensillum styloconicum. The amino acid receptor in this sensillum, however, is not affected. In contrast, neither azadirachtin nor salannin influences the sensitivity of any of the receptor cells in this sensillum.
The adaptation rate of the deterrent receptor is low in comparison to that of the two sugar receptors.
A significant correlation is found between the antifeedant indices of the four neem compounds tested at three different concentrations, and the responses of the deterrent receptor to these compounds at similar concentrations. It is concluded that when this insect species feeds on its natural foodplant (i.e. cabbage), the deterrent effect of neem compounds is mediated solely via the medial deterrent receptor, whereas inhibitory effects on the sugar and glucosinolate receptors do not play a significant role.     

Behavioural responses of young cape gannets Sula capensis to high ambient temperatures

A young Cape Gannet Sula capensis responded to high ambient temperatures in the laboratory by standing, gular fluttering with raised head and open bill, wing drooping, defaecating at a fast rate close to or onto the feet, “paddling”; in the excreta, and increased breathing rate. Standing initially caused a decline in foot temperature which rose with rising ambient temperature. Gular flutter and wing drooping assisted the bird in tolerating heat stress. Reduction in heat‐load occurred when standing on a wet surface, presumably due to evaporative heat loss (of excreta on the feet = urohidrosis) and an enhanced conduction of heat to substrate. Field observations confirmed that young Cape Gannets defaecate onto their feet at high ambient temperatures. This species appears preadapted for this behaviour since it builds a solely guano nest, defaecating onto the rim which is compacted by “paddling”;.     

Multisensory signals trigger approach behaviour in the fire-bellied toad Bombina orientalis: sex differences and call specificity

Animal communication often involves multimodal signals, and interactions between sensory modalities can trigger unique responses in receivers. Response to social signals was investigated in fire-bellied toads by exposing them to playback of male calls (advertisement and release calls) and a video clip of a male conspecific in the laboratory. The cues were presented in isolation and as a combined bimodal stimulus, and approach frequency, latency to approach and time spent around the stimulus source were measured. No positive phonotaxis was observed toward the advertisement call, both during the day and during a phonotaxis trial performed at night. However, females, but not males, approached with greater frequency, lower latency, and spent more time near the source of the bimodal stimulus in an experiment involving the advertisement call. Female response was specific to the advertisement call, as approach was not increased when the release call was used. Males, on the other hand, did not show increased approach in the advertisement call experiment, but approached with greater frequency the bimodal stimulus involving the release call within the first minute of stimulus presentation. The findings suggest that females orient toward calling males and that males eavesdrop on release calls, but in both cases a visual stimulus is also needed to trigger a response. Social approach in Bombina orientalis is thus dependent on multisensory cues, and the nature of the interaction between sensory modalities depends on receiver sex and call type.     

Behavioural responses of wheat stem sawflies to wheat volatiles

1 Adult wheat stem sawflies Cephus cinctus, pests of cultivated cereals that also infests wild grasses, migrate into wheat fields where they oviposit in elongating, succulent stems.
2 Volatiles released by wheat plants at susceptible stages were analyzed to determine potential semiochemical compounds. Seven major compounds were identified and quantified.
3 A Y-tube bioassay was developed to evaluate upwind orientation of adult sawflies in response to an airstream that passed over elongated wheat plants. The bioassay was also conducted with synthetic volatile compounds. The compounds were tested using a range of concentrations spanning those identified in the airstream passing over wheat plants.
4 A significant number of adult females were attracted to wheat plants when given a choice of either purified air or the air passing over plants.
5 A significant number of female C. cinctus were attracted to ( Z )-3-hexenyl acetate, β-ocimene, and ( Z )-3-hexen-1-ol, but were repelled by 6-methyl-5-hepten-2-one. Females did not respond to ( E )-2-hexenal, or ( E )-2-hexenyl acetate. The behavioural responses were concentration dependent; the highest tested concentration of ( Z )-3-hexenyl acetate was repellent to females of this species.
6 Adult males did not discriminate between air passing over wheat plants and air from a purified airstream. Males did not respond to any tested synthetic compound at any concentration.
7 The present study demonstrates for the first time that adult females of wheat stem sawfly display innate behaviours in response to synthetic volatiles. These results provide a basis for the potential development of resistant wheat varieties and for the development of semiochemically-based pest management.