In this paper, we describe the hitherto largely overlooked effect of temperature on the pupil of insect compound eyes. In the turnip moth Agrotis segetum and in two other nocturnal insects with superposition eyes, the lacewing Euroleon nostras and the codling moth Cydia pomonella, the pupil not only opens and closes with changes in the ambient light level, as expected, but also with changes in temperature in the absence of light. In complete darkness, the pupil of A. segetum responds over a wide range of temperatures, with the pupillary pigments migrating to a light-adapted position when the animal is exposed to either low or high temperatures. At temperatures between 21.0 and 22.7 C, the pigments migrate to the fully dark-adapted position, resulting in an open pupil and maximal eye glow. Pupil closure at high temperatures shows two distinct thresholds: the first at 23.8+/−0.7 C and a second some degrees higher at 25.7+/−1.2 C (means +/− s.d., N=10). Temperatures exceeding the first threshold (the activation temperature, T(a)) initiate a closure of the pupil that is completed when the temperature exceeds the second threshold (the closure temperature, T(c)), which causes rapid and complete migration of pigment to the light-adapted position. All temperatures above T(a) affect the pupil, but only temperatures exceeding T(c) result in complete closure. Temperatures between T(a) and T(c) cause a slow, partial and rather unpredictable closure. The lacewing and the codling moth both show very similar responses to those of A. segetum, suggesting that this response to temperature is widespread in superposition eyes. The possibility that the ambient temperature could be used to pre-adapt the eye to different light intensities is discussed.
New funding schemes for junior faculty staff
In celebration of our 100th anniversary, JEB has launched two new grants to support junior faculty staff working in animal comparative physiology and biomechanics who are within five years of setting up their first lab/research group. Check out our ECR Visiting Fellowships and Research Partnership Kickstart Travel Grants.
JEB@100: an interview with Monitoring Editor Stuart Egginton
Stuart Egginton reveals how he overcame the challenges of being a comparative physiologist in a medical school and how he would tell his younger self to trust his instincts when pursuing new ideas.
Travelling Fellowships from JEB
Our Travelling Fellowships offer up to £3,000 to graduate students and post-doctoral researchers wishing to make collaborative visits to other laboratories. Next deadline to apply is 27 October 2023
Feedforward and feedback control in the neuromechanics of vertebrate locomotion
Auke J. Ijspeert and Monica A. Daley provide an overview of key knowledge on feedback and feedforward control gained from comparative vertebrate experiments obtained from neuromechanical simulations and robotic approaches. Read the full Centenary Review Article here.
Light fine-tunes electric fish pulses to keep them in the shade
Weakly electric fish perceive their surroundings through electric chirrups and now Ana Camargo & colleagues have revealed that light fine-tunes the fish's electric pulses to ensure that they remain scheduled beneath the mats of vegetation they use for shelter, avoiding penetrating beams of light that could give them away.
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