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Abstract

Earwigs The common European earwig (Forficula auricularia Linnaeus) is a polyphagous insect from the order Dermaptera. Forficula auricularia is common in most temperate regions, being native to almost all of Europe, north Africa, and even parts of north-western Asia. It is also a successful invader of North America, Australia, and New Zealand. They are crawling insects; despite having functional wings these are almost never used (Phillips, 1981). For part of the year (June-October) F. auricularia spends its time in bushes or trees, hiding in small crevices during the day and emerging at night to forage. It is widely accepted that F. auricularia’s exoskeleton and faeces contain an aggregation pheromone, but despite this the pheromone and its mode of action are poorly understood. Several lab studies have shown F. auricularia preying readily on a number of important horticultural pests, which have been corroborated in field studies. Agricultural impact Forficula auricularia is considered as both a pest and a beneficial natural enemy depending on the agricultural system in question. Particularly in soft fruits, F. auricularia can be an important pest at high population densities, damaging budding shoots, leaves, or soft fruits themselves. In contrast, harder fruits and particularly apples, pears, and citrus fruits, tend to benefit from the presence of F. auricularia. This appears to result from the combination of a reduced ability of the earwig to harm these fruits, as well as a preference to consume pest insects over plant material. Studies in the lab and the field have demonstrated the efficacy of F. auricularia in controlling certain pest populations. However, it is important to recognize that much is still poorly understood about F. auricularia’s foraging behaviour, and that F. auricularia’s suppression of various pests has been inconsistent in field trials Woolly Apple Aphid The woolly apple aphid (Eriosoma lanigerum (Hausmann)) (WAA) is an economically important pest of apple trees worldwide. WAA probably originated in North America, but its distribution is now global. As with most aphid species, WAA populations can increase extremely rapidly, most colonies in favourable conditions are all female and reproduce by parthenogenesis (asexual reproduction in which females produce clones of themselves). A distinction is made between colonies of WAA infesting roots and those infesting other areas of the tree as they require entirely different approaches to reduce their populations. RFID tracking Radio-frequency identification (RFID) is a technology used to locate and identify objects that have had a tag attached to them. When studying animals, passive RFID tags are most commonly used. These require no battery as they are powered by the electromagnetic field surrounding an antenna. This causes the tag to send an identifying number to the tag reader, which interprets and logs the data received. These systems are close range and at a fixed point (usually), very different from the radio and satellite tracking tags made famous in studies on the migration of geese, sharks, etc. In RFID studies, if a fixed point can be identified where the tagged animals must pass through or visit then the technology is extremely powerful, since it allows the autonomous gathering of data on which animals visit a location and when. In ornithological studies for example, RFID readers have been placed in locations such as nest boxes, bird feeders, and artificial perches. RFID readers are also often incorporated with other autonomous data gathering devices, such as scales or video cameras. This application is effective because it can convert what might otherwise be anonymous data (weight or appearance in the examples given), and pair this data with the RFID tag’s identification of the individual. RFID in entomology When it comes to invertebrates, RFID tagging projects on bees have dominated. (Eu)social, colony-based insects are ideal subjects for RFID because all individuals must pass in and out of their communal nest, providing a perfect location for the RFID readers to be placed. This has allowed detailed studies into the foraging behaviour of bumble- and honey-bees. Nevertheless, there are RFID studies on a wide variety of insects. Many of the studies on non-eusocial insects use RFID tags as a less intrusive substitute for mark-release-recapture methods, employing mobile RFID readers and repeated measurements to create a time series of an individual’s location without disturbing them. It should be mentioned that there is a concerted, ongoing effort to push the boundaries of RFID systems. Particularly, by extending the detection range of passive tags, or miniaturising active ones, so that live location data can be produced by these systems.

Description

Objectives (how the central hypothesis will be tested):

1. Investigate earwig foraging behaviour within apple orchards.
2. Investigate earwig refuge use and the distribution of this insect within apple orchards.
3. Identify factors (environmental or management) which influence earwig foraging and distribution.
4. Determine how environmental or management factors affect earwig predation of the woolly apple aphid.
5. Test methods which might be used to improve the reliability of earwig control of the woolly apple aphid.