Subterranean beetles of the tribe Leptodirini show a wide range of life cycle modifications, including a reduced number of larval instars, an increase in egg size and a reduction in their number per clutch. In this work researchers show that, unexpectedly, developmental timing and duration are highly conserved among species irrespective of these life cycle modifications. They also found a strong correlation of the size of the first instar larva with adult size, also regardless of geographical location, habitat or life cycle type. These results suggest that timing and energy requirements impose deeply conserved constraints during development.

Reference Article: Cieslak A, Fresneda J, RiberaI. 2014 Developmental constraints in cave beetles. Biol. Lett. 10: 20140712. http://dx.doi.org/10.1098/rsbl.2014.0712