Simmons, P.J. (2024). Scaling of sense organs that management flight: Measurement and sensory cell variety of dipteran fly halteres. Journal of Zoology, vol. 322, pp. 12-23. https://doi.org/10.1111/jzo.13117
Dipteran (‘true’) flies are amongst probably the most aerobatic bugs, and one of many largest insect orders. They’re characterised by a single pair of power-providing wings, the hind wings being modified into drumstick-like sensory constructions, the halteres. Halteres act as gyroscopes (as proven by JWS Pringle (1948) in a paper that could be a actual tour-de-force) offering data that’s essential to a fly’s aerobatics. The knowledge comes from tiny pressure gauges, i.e. mechano-sensory cells on the floor close to a haltere’s joint with the thorax. Haltere form and the association of their sensory cells differ between totally different fly teams (Agrawal et al., 2017), however haltere measurement has not been measured systematically.
In a challenge following my retirement from Newcastle College, I investigated whether or not giant flies have longer halteres than smaller flies, and whether or not giant flies’ halteres bear extra sensory cells and so collect extra data than these of small flies. Little is thought about how the dimensions and construction of sense organs differ with physique measurement in animals, excluding eyes by which bigger animals have smaller eyes in relation to physique measurement in contrast with smaller, related animals.
I discovered that bigger flies do have longer halteres than smaller ones, however in relation to physique measurement they’re shorter – the identical form of scaling discovered with eyes. Crane flies have significantly lengthy halteres in contrast with hover flies or blow flies. Haltere size is proportional to wing size – it is necessary that each constructions beat up and down on the similar frequency throughout flight. The dimensions of the swollen bulb-like finish of a haltere was typically bigger in relation to haltere size in small flies.
The variety of sensory cells is more-or-less fastened inside a specific group of flies. It doesn’t differ between species which have giant and small physique sizes, or between giant and small flies of the identical species. Nevertheless, the variety of sensory cells does differ between totally different teams. In my pattern, horseflies had many greater than hover flies or ‘calyptrates’, which embody houseflies and blow flies. It’s not clear why horse flies ought to be endowed with so many haltere sensory cells – we all know little about their flight behaviour. It is perhaps that the extra common association of sensory cells into rows in hover flies and calyptrate flies permits them to work extra effectively, so these flies want fewer of the sensory cells than horse flies do. Crane flies had comparatively few of the sensory cells, maybe related to their slower, much less aerobatic flight.
Peter Simmons
References:
Pringle, J. W. S. (1948). The gyroscopic mechanism of the halteres of Diptera. Philosophical Transactions of the Royal Society B – Organic Sciences, vol. 233, pp. 347–384. https://doi.org/10.1098/rstb.1948.0007
Agrawal, S., Grimaldi, D. & Fox, J. L. (2017). Haltere morphology and campaniform sensilla association throughout Diptera. Arthropod Construction & Growth, vol. 46, Situation 2, pp. 215-229. https://doi.org/10.1016/j.asd.2017.01.005