Eggs and oviposition in chrysomelid beetles

Abstract

The general biology of insect eggs including Chrysomelidae has been brilliantly reviewed in the last publications of Prof. Howard Hinton, published posthumously in three volumes. A particularly useful review of the egg-laying habits of the Chrysomelid beetles of northern Europe is to be found in Cox. The number of eggs laid varies greatly: a single Leptinotarsa decemlineata Say (Colorado potato beetle) female has been lay as many as 2804 eggs while Promecotheca reichei Baly lays only 16-25. The number of eggs laid appears to be related to temperature, greater numbers being laid in warmer climes. When large numbers of eggs are laid in a group these eggs usually contain initially poorly-developed embryos which develope to maturity over a week or several weeks. On the other hand, eggs laid singly usually contain well-developed embryos which hatch comparatively quickly. Chrysomelid beetles can be quite long-lived, especially the larger and high altitude species: some Paropsis and Chrysomela species live for two years or more as adults. These species may lay large numbers of eggs over their life span though in comparatively small numbers at any one time. Some species do not start to breed until they are in their second year. Most chrysomelids mate frequently, though a few, e.g. Plagiodera versicolora Laich, may mate in the autumn and retain the sperm in their bodies to fertilize the eggs in the following spring.