Uetz GW, Roberts JA, Clark DL, Gibson JS, Gordon SD. 2013. Active space of multimodal signals of wolf spiders in a complex litter environment. Behavioral Ecology & Sociobiology. 67:1471-1482

Uetz GW, Roberts JA, Clark DL, Gibson JS, Gordon SD. 2013. Active space of multimodal signals of wolf spiders in a complex litter environment. Behavioral Ecology & Sociobiology. 67:1471-1482

by | Mar 14, 2013 |

Abstract Multimodal signals may compensate for environmental constraints on communication, as signals in different modalities vary in efficacy. We examined the influence of complex microhabitats on transmission of vibratory and visual signals of courting male Schizocosa ocreata wolf spiders (Araneae: Lycosidae) with laser Doppler vibrometry (LDV) and behavioral observations in lab and field. We measured maximum potential detection distance of visual and vibratory signals by females in laboratory mesocosms, recorded vibration signal attenuation on different substrates, and estimated transmission distances for male vibration signals in the field. We also determined effective line-of sight visual detection distances in the field with laser distance measures. Together, these data were used to estimate the potential and effective active space of multimodal signals. LDV measures show leaves are highly conductive substrates for wolf spider vibratory signals compared to others (soil, wood, rock). For both visual and vibratory modes, lab estimates of maximum potential distance for signal transmission and detection (behavior studies) exceeded estimates of effective active space (signal attenuation, “vanishing point,” and “line-of-sight” measures). Field estimates of transmission distance for signal modes overlap, such that in close range (<20 cm), vibratory signals are more likely to be detected, while farther away, visual signals are more likely to be seen. These findings thus support current  hypotheses regarding how multimodal communication might extend the range of overall signal active space or compensate for environmental constraints. Uetz GW, Roberts JA, Clark DL, Gibson JS, Gordon SD.  2013.  Active space of multimodal signals of wolf spiders in a complex litter environment.  Behavioral Ecology & Sociobiology. 67:1471-1482...
Gordon SD, Uetz GW. 2011. Multimodal communication of wolf spiders on different substrates: evidence for behavioral flexibility. Animal Behaviour. 81:367-375.

Gordon SD, Uetz GW. 2011. Multimodal communication of wolf spiders on different substrates: evidence for behavioral flexibility. Animal Behaviour. 81:367-375.

by | Dec 9, 2010 |

Communication in complex environments poses challenges of potential loss of intended messages, but some animals may compensate by using multimodal signalling. Courtship displays of male Schizocosa ocreata (Hentz) wolf spiders are multimodal, consisting of visual and seismic signals. The microhabitat of S. ocreata is complex, including leaf litter, wood/bark, soil and rocks. Results from laser vibrometer measurements in the present study indicated that leaf litter transmitted male courtship signals with greater efficacy. Mating success was significantly greater on leaf litter (∼85%) compared to other substrates (∼30%), even though latency to male courtship did not vary among substrates. Given these results, selection should favour spiders that increase their mating potential on nonconducting substrates. We tested whether spiders detect substrate differences in a choice test, and found that when males and females visited all substrates, they spent significantly more time on leaf litter. We isolated courting male spiders on each substrate and scored courtship behaviours to see whether signals varied with substrate. Males used significantly more visual signals (waves and arches) on substrates that attenuated seismic signals (soil and rocks), but other behaviours showed no differences. Taken together, these results suggest that combined visual/seismic components of multimodal displays may serve as ‘backup signals’, ensuring reception under different environmental conditions. Results also suggest that male S. ocreata have the flexibility to compensate for environmental constraints by seeking microhabitats with more effective vibration conduction properties, and/or by increasing visual signals on substrates where seismic communication is less effective. Gordon SD, Uetz GW.  2011.  Multimodal communication of wolf spiders on different substrates:  evidence for behavioral flexibility.  Animal Behaviour. ...