Taxonomic name: Radumeris tasmaniensis (Saussure, 1855)
Synonyms: Campsomeris tasmaniensis (Saussure)
Common names: burmeister (Mexico), guerin (India), scoliid wasp, yellow flower wasp
Organism type: insect The scoliid wasp, Radumeris tasmaniensis, is native to Australia and Papua New Guinea. It is a solitary ectoparasite of beetles in the Scarabaeidae family; laying its eggs on the paralysed larvae. Since 2000 the species has been confirmed as present at three New Zealand sites and is precipitating concerns about the conservation of native beetles. Description
Members of the family Scoliidae are solitary ectoparasites of scarabaeid larvae (and occasionally Curculionidae larvae). They usually have curled or strongly curved antennae and both sexes are winged. Scoliidae have a characteristic flying pattern; they fly on a horizontal plane only a few inches above the ground in a regular circular “figure 8” course. Eggs of the Scoliidae family range in length from only 2mm to 4mm. They are about a quarter less wide than they are long, with both poles rounded and a slightly wider anterior end. The ventral side is almost straight and the dorsum is slightly convex.
Females scoliid wasps (Radumeris tasmaniensis) are about 3cm long with a 4cm wingspan and have a large robust body with a broad abdomen. Males are about 2cm long with a 2.5cm wingspan and have a more slender body with a narrow abdomen. Females have a dark brown thorax, a narrow waist and a broad orange abdomen with narrow black stripes. Their underside has wide black stripes with narrow white stripes. Males have alternating black and yellow stripes on both the upper and lower surfaces. The female has short antennae about the same length as the width of the head; the male has longer antennae, about half the length of the forewings. Both male and female have orange to brownish wings, with very fine veins towards the wing tips. Similar Species
Campsomeris limosa, Campsomeris plumipes fossulana, Scolia affinlis, Scolia atrata, Scolia dubia, Scolia flavifrons, Scolia manilae
More
Occurs in:
coastland, host Habitat description
Radumeris tasmaniensis is an ectoparasitic (it lives on the outside of its host) and solitary in nature. Instead of forming a nest, the female tunnels into soil and locates a scarab beetle larva, which they sting and paralyse before laying an egg nearby. The larva then becomes a source of food for the young wasp as it grows. In its introduced range in Northland, New Zealand, R. tasmaniensis is reported in isolated coastal spots. General impacts
Because scoliid wasps parasitise scarabaeid beetles they have the potential to cause declines in beetle populations in this family. The scoliid wasp is a parastoid of large (>1.5 g) scarab larvae (Willoughby et al. 2001). Evidence and research in this area is deficient.
In New Zealand there is a concern that native beetles could be affected by the presence of the scoliid wasp, which has established itself at three sites in the north of the country (Willoughby et al. 2001).
Wasps may bring with them a financial burden too. They compete with native bees for nectar needed to make honey, reducing honey production (Landcare Research 2007).
Wasp stings are painful and can be life-threatening to some people. A small proportion of the population will have a severe allergic reaction (called anaphylactic shock), which can be fatal unless treated promptly (Landcare Research 2007). Uses
There do not appear to be any known uses for Radumeris tasmaniensis, but other wasps in the Scoliidae family have been used for the biological control of scarabaeid beetles (e.g. S. manilae was introduced from the Philippines into Hawaii to control Anomala orientalis).
Research into naturally produced compounds in parasitic wasps could reveal chemicals with useful properties, such as anti-microbial activity (Dani et al. 2003). This is because insects that are parasitised by wasps have impaired immune systems (and a greater susceptibility to opportunistic pathogens), which compromises the survival of the wasp progeny. The production of antimicrobial factors by parasitic wasps could protect the host larva from microbial infection allowing it to live longer and provide the wasp larvae with food for a longer period of time. This production of antimicrobial compounds in wasp venom is an interesting target of current research (Dani et al. 2003). Geographical range
Native range: Radumeris tasmaniensis occur naturally in Australia (mainly Queensland) and Papua New Guinea (Krombein 1963).
Known introduced range: New Zealand (in the Northland region) Management information
Preventative measures: The early detection of establishing populations is important as the next line of defence after initial quarantine procedures. Landcare research has conducted research into generalised invertebrate surveillance techniques in recognition of the gap in biosecurity surveillance. These include malaise traps, mini-malaise traps, window traps, sticky traps, pitfall traps, UV light traps, flat ant traps, baited ant pottles, spurr wasp traps, ground bottle traps, yellow pan traps and beating. Of these, malaise traps, mini-malaise traps, window traps, sticky traps (for small wasps), UV traps, spurr wasp traps and ground bottle traps were found to be effective at catching wasps. Please follow this link for descriptions of trapping methods: http://www.landcareresearch.co.nz/research/biocons/invertebrates/id_surveillance.asp> There are two ways of reducing a local wasp problem - either finding and destroying all nests in the area, or using poison bait (Landcare Research 2007). Manual destruction of nests over large areas of shrub land is likely to be difficult and labour intensive (Toft and Harris 2004). The advantage of poison bait is that foraging wasps carry the poison back to the nest, meaning it is unnecessary to locate nests or approach those that are very large or difficult to get at (Landcare Research 2007).
Both methods will only alleviate the problem for the current season and workers foraging for food will reinvade the area. The area will almost certainly be reinvaded next season by queen wasps, which can fly up to 30 kilometres in their search for suitable nesting sites (Landcare Research 2007).
Biological: Biological control has been used in attempts to achieve widespread control of wasps. For more information on biological control of wasps please follow this link: http://www.landcareresearch.co.nz/research/biocons/invertebrates/Wasps/biocontrol.asp Nutrition
Larvae of Scoliidae hatch out of eggs laid on paralysed host grubs. Wasp larvae then devour the host larvae, which are rich in protein. Adult Scoliidae obtain carbohydrate-rich meals derived from flower nectaries, especially those in the Umbelliferae family (but a range of flowers are exploited, including sweet potato and orange flowers). Reproduction
Mature male Scoliidae usually emerge from cocoons before females and mating occurs as soon as females emerge from the soil. The female must then locate an appropriate host grub to lay her egg on (usually a member of the scarabaeid beetle family). Depending on the species of scarabaeid, the host larva will be found buried underground at a depth of up to 40cm, or may simply be found lying on the soil surface. The female Scoliidae will burrow extensively to locate host larvae and can take advantage of the pre-existent burrows made by the host larvae to track them down. She then stings the host larva several times in the thoracic region to paralyse it and buries it to a depth of between 25cm and 1m. The depth necessary will depend on the soil type (as in sandy soil the larvae are buried at a greater depth than in clay or loam soil). Female Scoliidae can produce a maximum of 2 eggs per day in optimum conditions. For example Campsomeris tasmaniensis Sauss laid 95 eggs in 70 days (Illingworth 1921). C. tasmaniensis and C. radula females have been noted to produce mostly male progeny with an occasional female among them (Illingworth 1921). Lifecycle stages
Most Scoliidae have a single annual reproduction period which may increase to 2 or 3 periods in some climates (such as in Korea). Development is prolonged at reduced temperatures (ie: in cold climates). The incubation period of eggs is between two to three days in optimum conditions. The larval period is usually 6 to 9 days, and this stage is followed by the construction of a cocoon (the form of which varies between different species). The cocoon stage usually lasts between 30 and 40 days in summer, but most species hibernate within the cocoon (in the mature larvae stage) with the onset of winter. Reviewed by: Dr. Barbara Barratt Senior Scientist AgResearch Invermay, Mosgiel, New Zealand.
Compiled by: IUCN/SSC Invasive Species Specialist Group (ISSG) with support from the Terrestrial and Freshwater Biodiversity Information System (TFBIS) Programme (Copyright statement)
|
|
Last Modified: Tuesday, 28 November 2006
|
