Miniature Insects

Smallest Fly

Illustration of world’s smallest fly showing its small size relative to the House fly.
Illustration: Inna Strazhnik.

Scale is important in the interactions of the biological and the physical world. As humans, we experience a narrow range of scale, from a minimum of one foot to a maximum of eight feet which is less than one order of magnitude. Imagining what life must be like at vastly smaller size is difficult- outside our experince. Even the largest insects are an order of magnitude smaller than human adults. The range in size from the heaviest adult insect to the smallest is over 5 orders of magnitude, the largest insects being over 10000 times heavier than the smallest. It is remarkable that the insect body plan can accommodate such a wide range of sizes.

Alexey Polilov reviews* some of the adaptations of the smallest insects. One of the notable consequences of small size is that the reduction in volume and mass is much greater than the reduction in surface area. An insect that is 10-fold smaller in length, will have a 100-fold reduction in surface area and a 1000-fold reduction in volume. That means less volume to store water and accommodate internal structures. Consequently, the thickness of the cuticle is reduced and internal bracing (apodemes and tentorium) may be reduced or absent in the smallest insects. These adaptations may be necessary to accommodate the brain and muscles of the head and body. The weight that must be contained by the exoskeleton of a small insect is less and a much thinner cuticle is sufficient. Many larvae of the smallest insects are parasitoids that are protected by their location inside the host, often swimming in the host’s fluids which buoy further the already tiny weight.

*Alexey Polilov. 2015. Small Is Beautiful: Features of the Smallest Insects and Limits to Miniaturization. Annu. Rev. Entomol. 2015. 60:103–21

About jjneal

Jonathan Neal is an Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
This entry was posted in Biomaterials, by jjneal, Taxonomy. Bookmark the permalink.

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