Thursday, 6 March 2008
Bugs Are More Complex Than We Think
The Bronze Orange bug, Musgraveia sulciventris (Stål).
Several groups of Bugs (Heteroptera) exhibit parental care to eggs or young (nymphs). Females don’t feed at this time. A wonderful review of this phenomenon in Australian species was provided by Monteith (2006). He provides accounts and photos of this activity among a number of bugs but especially the Tessaratomidae. This work should be consulted for other examples of this phenomenon in Australian bugs. This is a family of over 50 genera and 240 species of large bugs. They are Old World in their distribution with one of the three subfamilies, the Oncomerinae, mainly Australian. The Bronze Orange bug, Musgraveia sulciventris (Stål), is a common Australian example and occurs on native limes. It is a pest of cultivated citrus throughout Australia and familiar to most folk who have citrus trees. Oddly, it is one species that shows no maternal care of eggs or young.
A male Tectocoris diophthalmus (Thunberg).
A female Tectocoris diophthalmus (Thunberg).
EF Dodd, son of FP Dodd, the "Butterfly Man of Kuranda, noted that the females of a bug in a related family, the Scutelleridae, Tectocoris diophthalmus (Thunberg) [see male and female above], brooded batches of up to 60 eggs. When threatened the female turned towards the intruder. It was later discovered that the bugs defend their eggs from attacks of parasitic wasps as well as other creatures. (A certain reader of this blog will recall that these bugs feed on the local Hibiscus Pyramid trees in Newcastle, New South Wales where children refer to them as “Jewel Beetles”.)
A female Lyramorpha parens Breddin gurading her young.
A Lyramorpha parens attracted to the light sheet.
In Kuranda are there are several tessaratomids that we see commonly. Locals refer to them as “stink bugs” for obvious reasons. Lyramorpha parens Breddin is one such bug and Geoff Monteith notes that this species is found in tropical north Queensland with a smaller, more widespread species, L. rosea Westwood occurring along the south-eastern coast from Victoria north to Mt Woowoonga in southern Queensland, Monteith (2006). Where some species of tessaratomids show adaptations to brooding by having a flattened body, L. parens have more or less normal bodies. According to Monteith the eggs are arranged in rows of 6, 6, 7, 8, 7, 6. As you can see, females stay with the young for a long period. The colour of the young is certainly aposematic, suggesting a bitter experience to any bird or lizard that tries to dine on the bugs.
Thanks to Geoff Monteith for helpful comments.
Monteith G. B. 2006. Maternal care in Australian oncomerine shield bugs (Insecta, Heteroptera, Tessaratomidae). Denisia 19, zugleich Kataloge der OØ. Landesmuseen Neue Serie 50: 1135-1152.