Introducing the Hymenoptera: much more than aggressive stingers and jam jar raiders.

The Hymenoptera are one of the dominant life forms on Earth in both the number of species and in the diversity of life styles; however it is impossible to guess how many individual species there are with any accuracy (Austin & Dowton 2000). The order is so diverse there is no common name for the order like that given to the other insect orders, for example Coleoptera are commonly known as beetles, and Lepidoptera are referred to as butterflies and moths.

Four features are the main factors that separate the Hymenoptera from the rest of the insects and are crucial to the evolution and diversity of the order (Austin & Dowton 2000, Gould & Bolton 1988). These four factors are:




Figure 1: Aphidius ervi - biocontrol wasp attacking pea aphids. A parasitic wasp lays its egg inside a host,
the young feed on the host.
Image courtesy of www.alexanderwild.com.

1. Ovipositor is used for egg laying and venom delivery

 

2. Food is provided to the larvae by adults (bees/wasps create a cell for young and feed until pupation) or egg is laid in food source (such as parasitic wasps).

3. Larvae eat a range of foods – waste is stored in a gut cavity that does not form an intestine until the final stages of development.

 

4. Haplo-diploid sex determination: males are developed from non fertilised eggs therefore only receive mother’s genetics and females develop from fertilised eggs so genes are provided by mother and father.

Figure 2: honey bee feeding larvae inside cell.
Image courtesy of Maryann Frazier/Penn State.

 



These factors, along with environmental pressures have contributed to the amazing diversity of life seen in the order – there are parasites, parasites of parasites, herbivores, seed eaters, gall formers, specialised predators, pollinators and both social and solitary species (Austin & Dowton 2000).

 

 

 

Social Hymenoptera are said to represent the absolute peak of the evolutionary summit of invertebrates – social structures, agriculture and slave-keeping were present in Hymenopteran society well before humans even picked up their first tool (Gould & Bolton 1988). The video below shows how parasitic wasps can turn other insects into their 'slaves' or 'zombies'.

 

It has been suggested that the diversity of Hymenoptera is an example of how environmental pressures and ancestry can influence the evolution of a species and are useful subjects for the studies of how these processes can both play a part in understanding insect evolution (Strand 2000). It could be argued that the Hymenoptera are possibly the most important insects to evolutionary research.

Stay tuned for more from the exciting world of Hymenoptera.  

References:

Austin, AD & Dowton, M 2000, 'The hymenoptera: an introduction’, in AD Austin & M Dowton (ed.), Hymenoptera: evolution, biodiversity and biological control, CSIRO Publishing, Melbourne, pp. 3-7.

Gould, I & Bolton, B 1988, The hymenoptera, Oxford University Press, Oxford.

Strand, MR 2000, 'The effects of life history on development of the hymenoptera’, in AD Austin & M Dowton (ed.), Hymenoptera: evolution, biodiversity and biological control, CSIRO Publishing, Melbourne, pp. 11-16.

Figure 1: Alex Wild: The diversity of insects, viewed 10 March 2015. http://www.alexanderwild.com/Insects/Insect-Orders/Bees-Wasps-and-Sawflies/i-W8t97Kt/2/XL/Aphidius12-XL.jpg
 
Figure 2: Penn State News 2010, Penn State University, Pennsylvania, viewed 10 March 2015. http://news.psu.edu/story/301619/2014/01/27/research/common-crop-pesticides-kill-honeybee-larvae-hive

youtube video "Zombie caterpillar controlled by voodoo wasps": New Scientist 2008, Reed Business Information Ltd, viewed 10 March 2015. http://www.newscientist.com/article/dn14053