Is L15 the Mantid LGMD

As we have noted, one of the drawbacks with doing psychophysical or neurophysio-logical studies with highly abstracted visual stimuli (e.g., arbitrarily sized dots, gratings, and stripes) is that it can be difficult to relate the organismal or cellular responses to real-world behavior. However, this difficulty notwithstanding, one of the large lobula cells characterized by Berger (1985) in Mantis religiosa (his L15) is provocatively similar to the orthopteroidean LGMD in morphology, in response...

Bending the Rules Color Vision and Polarization Vision in the Same Part of the

It is expected that in a given rhabdom, intensity will be used to code only one additional qualitative parameter either color or polarization. This is because each component cell can produce only a quantitative neurological signal representing its own photon catch and its efficiency in absorbing and transducing the light. The latter is influenced by the cell's degree of adaptation to a given light intensity, but a photore-ceptor's absorption efficiency depends on its spectral sensitivity range...

Auditory Cues that Identify Conspecifics

Male mate location calls are species-specific, with a fixed structure of one to six syllables, with the exception of those made by Pneumora inanis, in which a fifth syllable may be repeated for several minutes figure 11.2 . The final syllables range in length from 266 to 3800 ms mean S.D. 988.5 1085 and are always resonant. With the possible exception of B. membracioides, the shape of the final syllable has a linear or exponential rise and a relatively sharp decay. Carrier frequencies range...

Auditory Cues that Identify Mates

Mature male bladder grasshoppers are responsible for initiating pair formation by duetting and phonotaxis. They solicit an interaction by repeating a simple, stereotyped, high-intensity call at intervals upward of 4 s, and by flying distances up to 500 m between calls. An acoustic response from a philopatric female elicits more directed male movement and ends in pairing, with no apparent courtship behavior or contribution from other sensory modalities. In a typical pneumorid, for instance,...

Significance of the Polarization and Wavelength Sensitivities of the Ventral Retina

Unfortunately, as yet there has been no successful electrophysiological investigation of the eye of the firefly squid. Michinomae et al. 1994 provided evidence that the two ventral retina visual pigments are never found in the same rhabdom. This suggests strongly that individual rhabdoms cannot provide a wavelength-derived contrast signal. That is, intrarhabdomal color opponency is unlikely in the firefly squid. Having two different visual pigments overlying each other means that the most...

What Firefly Squids See The Retina of Watasenia scintillans

Watasenia scintillans is a small species of squid belonging to the family Enoploteuthi-dae. The adults reach only 60 mm in body length and spend most of their time living in semidarkness at a depth of about 400m. Watasenia is unique in possessing three different visual pigment chromophores, which combine with a protein opsin to form three different visual pigments. Each photoreceptor cell contains only one of these visual pigments, but two types of photoreceptors receive light from the same...

Life in the Twilight Zone Proposed Functions of the Firefly Squid Ventral Retina

The firefly squid's ventral retina receives the strongest incident light emanating from directly above in a narrow, near-vertical beam Michinomae et al., 1994 . In the squid's deep-sea habitat, this light has a narrow spectrum, with a peak at around 470 nm curve 6 in figure 9.23 Lythgoe, 1972 Seidou et al., 1995 , so this is the wavelength where receptors sensitive to either color information or polarization patterns function at their best. Underwater, the percent of polarization varies little...