Bees Use Different Visual Cues When Viewing Flowers and Landscape Image Motion

<p>Although bees see flowers in colour, they do not analyse the colours of the landscape image that moves across the eye as they fly. Their perception of landscape motion is colour-blind; motion vision is driven solely by a single spectral receptor type, the bees' green receptor. This is reflected in the distance code of the dance: the more green contrast is present in the scene, the further bees ‘think’ they have flown. (Figure design: F. Bock, Beegroup Würzburg.)</p

A honeybee queen surrounded by her retinue.

<p>There are numerous behavioural, physiological, and anatomical differences between queens (which can lay up to 2,000 eggs per day) and sterile workers, even though they are identical at the genetic level. Upon emergence from the pupae, new queens engage in a series of duels with rival queens. The single survivor will leave the hive for 1–5 mating flights, during which she visits sharply delineated leks—congregation areas used solely for mating that might be several kilometres from the hive, where hundreds of drones typically await. Queens will mate with an average of 12 drones, who die shortly afterwards since the explosive ejaculation ruptures the everted genitals. A mated queen then returns to her native hive; egg laying begins shortly afterwards, and she will typically not leave the colony again unless a new queen is raised in the subsequent year, in which case the old queen leaves the hive with a large swarm of workers to relocate to a new home. Specialised workers who form the queen's retinue feed the queen and constantly groom and lick her, in the process picking up queen mandibular pheromone, which suppresses ovary development in workers <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1000532#pbio.1000532-Vergoz1" target="_blank">[24]</a>. Image: Helga Heilmann, BeeGroup Würzburg.</p

Social cognition in insects

Insects feature some of the most complex societies in the animal kingdom, but a historic perception persists that such complexity emerges from interactions between individuals whose behaviours are largely guided by innate routines. Challenging this perception, recent work shows that insects feature many aspects of social intelligence found in vertebrate societies, such as individual recognition, learning object manipulation by observation, and elements of cultural traditions. Insects also display emotion-like states, which may be linked to social behaviours such as rescuing others from danger. We review recent developments in insect social cognition and speculate that some forms of now-hardwired behaviour (e.g., nest construction) could have initially been the result of individual innovation and subsequent cultural spread, with evolution later cementing these behaviours into innate behaviour routines.</p

Dark and light adapted <i>I-V</i> relations compared in green and UV photoreceptor.

<p>A. Green photoreceptor. Superimposed membrane responses (upper traces) to square-wave current pulses (lower traces) injected in the dark (left) and during light adaptation. Resting potential in the dark is arbitrarily set to zero, and the vertical displacement of the light adapted resting level indicates the amplitude of the steady-state light-induced depolarization of the resting potential. B. As in <i>A</i>, for a recording from a UV photoreceptor.</p

Photoreceptor spectral sensitivity functions.

<p>Normalized, averaged data for green (A; n = 9), blue (B; n = 5) and UV (C; n = 6) sensitive photoreceptors. Error bars are ±1.0 SD.</p

Frequency Coding in the Human Ear and Cortex

<div><p>(A) The human ear and frequency mapping in the cochlea. The three ossicles incus, malleus, and stapes transmit airborne vibration from the tympanic membrane to the oval window at the base of the cochlea. Because of the mechanical properties of the basilar membrane within the snail-shaped cochlea, high frequencies will produce a vibration peak near the oval window, whereas low frequencies will stimulate receptors near the apex of the cochlea (locations for three frequencies indicated schematically). Information from the cochlear receptor cells is transmitted to the cochlear nuclei via the 8th cranial nerve, and on through the midbrain to the cortex. (Redrawn from Figure 12.3 in [<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0030137#pbio-0030137-b11" target="_blank">11</a>].)</p> <p>(B) Lateral view of the human brain, with the auditory cortex exposed. The primary auditory cortex contains a topographic map of the cochlear frequency spectrum (shown in kilohertz). (Redrawn from Figure 12.15A in [<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0030137#pbio-0030137-b11" target="_blank">11</a>].)</p></div

Mean parameters of light-off responses compared in all three spectral classes of photoreceptor.

<p>Left y-axis: light-adapted membrane potential ( = 1.0) normalized with respect to the dark resting potential (0). Mean light-adapted membrane potentials were 21.4±2.8 (green photoreceptors), 23.7±3.8 (blue), 24.4±3.2 mV (UV). <i>V</i>_peak plots the peak of the negative (repolarizing) response during a 30 ms pulse of darkness for green (green bars) blue (blue bars) and UV (grey bars) photoreceptors. <i>T</i>_peak is the latency to the peak negative response (right y-axis), measured from onset of dark pulse.</p

Two Wasp Species and Four Less-Than-Perfect and Palatable Mimics

<div><p>(A) Dolichovespula media; (B) Polistes spec.; (C) Eupeodes spec.; (D) Syrphus spec; (E) Helophilus pendulus; (F) Clytus arietes (all species European). Note that species C–F do not closely resemble any wasp species. The three hoverfly species differ in wing and body shape, antennal length, flight behaviour, and striping pattern from European wasps. One fly species (E) even has longitudinal stripes, which wasps typically don't. The harmless wasp beetle does not normally display wings, and its legs do not resemble those of any wasps.</p> <p>(Image Credit: (A, C, E, and F) by Rob Knell; (B and D) by Tom Ings)</p></div