ABSTRACT
Females of the wandering spider Cupiennius salei attach a sex pheromone to their dragline. Males encountering the female dragline examine the silk thread with their pedipalps and then typically initiate reciprocal vibratory courtship with the sexual partner. The female pheromone was identified as (S)-1,1'-dimethyl citrate. The male pheromone receptive sensory cells are located in tip pore sensilla and respond to touching the sensillum tip with female silk or pieces of filter paper containing the synthetic pheromone.
Subject(s)
Animal Communication , Behavior, Animal/drug effects , Citrates/pharmacology , Sensory Receptor Cells/drug effects , Sex Attractants/pharmacology , Spiders/physiology , Animals , Citrates/chemistry , Electrophysiology , Female , Male , Microscopy, Electron , Sensory Receptor Cells/ultrastructure , Sex Attractants/chemistry , Sexual Behavior, Animal/drug effectsABSTRACT
1. The threshold for detecting a change in temperature of a warm receptor in the wandering spider Cupiennius salei was determined by means of its frequency-dependent noise. To accomplish this, the warm receptor was regarded as a linear system consisting of two components, an amplifier (gain of the frequency response) and noise at its input added to the temperature stimulus (input noise density). 2. The frequency response was investigated with sinusoidal temperature modulations at frequencies between 0.05 and 12.8 Hz. The gain increased by 3.5 dB/octave in the frequency range between 0.05 and 6.4 Hz, from 0.19 to 3.1 degrees C-1. However, at the highest frequency, 12.8 Hz, the gain was reduced. 3. The noise density of the warm receptor was measured by the root-mean-square noise amplitude of the gain. The output noise density of the warm receptor, which describes the noise density of the gain, was constant at approximately 0.2 Hz-0.5 in the 0.05 to 6.4 Hz range, and increased at higher frequencies. The input noise density, given by the ratio of output noise density to gain, decreased by -2.7 dB/octave between 0.05 and 6.4 Hz, from 1.1 to 0.12 degrees C*Hz-0.5. 4. To define the threshold for detection of temperature changes from the input noise density, the energy of the threshold was equated to the energy of the noise. Assuming a signal-to-noise ratio of 1 and an upper limiting frequency of 10 Hz, the threshold estimated for the wandering spider Cupiennius ranges from 0.6 to 0.08 degrees C, depending on whether the inputs from only 1 or all 70 warm receptors of the 10 tarsal organs are combined.
