Predatory bush cricket (Saga pedo)
|Size||Length: 15 – 17 cm (2)|
Classified as Vulnerable (VU) on the IUCN Red List (1).
The predatory bush cricket possesses not only the title of the largest grasshopper in Europe, but also the largest insect on the continent (2). Also known as ‘the lobster of Provence’ (2), this species generally has a glossy, leaf-green body covered with spiky ‘teeth’ (2) (3), although some individuals may be paler, particularly on the underside (3). It has a long head and legs, and long, orange antennae (2) (3). Mature females can be distinguished from the males by their long ovipositor, a ‘tail-like’ structure used for laying eggs (3). This insect is also known as the ‘spiked magician’, due to the enchanting way in which it slowly waves its front legs back and forth when approaching prey, like a sorcerer casting a spell (2).
The predatory bush cricket has a scattered distribution across southern Europe (1). Its range stretches as far north as the Czech Republic, and from Portugal in the east to Kazakhstanin the west (1) (4).
The predatory bush cricket is found in a wide variety of habitats, including dry and wet meadows, hot and dry rugged terrain, shrubby hillsides and gorges, and agricultural land (5). It has been found from sea level up to altitudes of 1,500 metres, and typically remains hidden amongst grass stems in dense vegetation (5).
The predatory bush cricket has a remarkable life history, with the entire population consisting solely of females (there are two records of males in old literature, although these are doubtful) (6). Therefore, reproduction relies on parthenogenesis, where unfertilised eggs develop into ‘clones’ of the mother.
The female predatory bush cricket uses her ovipositor to deposit 25 to 80 eggs in the soil; in France this takes place during August and September (5). These eggs, which are amongst the largest known for insects, with a mean length and width of 11.9 millimetres and 3.8 millimetres respectively (4), usually hatch after two to three years of diapause, but may remain in the soil for up to five years. The eggs hatch after May, and the first adults are observed in July. Just four weeks after becoming an adult, the female begins egg-laying, which continues throughout the cricket’s incredibly brief life of just four to six months (5).
The predatory bush cricket is at its most active at twilight and during the night (4). It feeds upon grasshoppers, locusts and some mantids and, like other Saga species known for their cannibalistic tendencies, it will also feed on other bush crickets (5). On average, 11 grasshoppers or crickets are consumed each week (4). When prey is spotted, the cricket raises up on its hind- and mid-legs and moves towards the prey, slowly waving its fore-legs (2). Suddenly leaping on its unsuspecting victim, the prey is clasped with the fore- and mid-legs, and killed by a bite to the throat (5). The predatory bush cricket itself is prey for a variety of animals, including birds, rodents, lizards, frogs and toads (5).
The most significant threat to the predatory bush cricket is habitat loss and fragmentation, caused by human activities (7). Many factors contribute to this habitat loss, such as afforestation, intensive land-use for recreation, and overgrowth of areas by vegetation unsuitable for the bush cricket (4).
To tackle the threat of habitat loss and degradation, it has been recommended that traditional farming methods should be promoted and reinstated, since practices such as sheep and goat grazing and the removal of woody plants and seedlings would help limit the changes in vegetation that degrades suitable habitat for the predatory bush cricket (4). In addition, this cricket could be reintroduced into previously inhabited areas, by moving individuals from other, abundant populations (4).
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- Afforestation: the establishment of forest by natural succession, or by the planting of trees on land where they did not grow formerly.
- Antennae: pair of sensory structures on the head of invertebrates.
- Diapause: in insects, a temporary pause in development and growth.
- Ovipositor: a tail-like structure used for laying eggs.
- Parthenogenesis: a form of reproduction in which an unfertilised egg develops into a new individual. The individuals that result are genetically identical to their mother.
- Unfertilised: an egg (the female reproductive cell) that has not fused with a sperm (the male reproductive cell).
IUCN Red List (May, 2010)
- Blondel, J., Aronson, J., Bodiou, J-Y. and Boeuf, G. (2010) The Mediterranean Region. Biological Diversity in Space and Time. Third Edition. Oxford University Press, Oxford.
- Marshall, J.A. and Haes, E.C.M. (1988) Grasshoppers and Allied Insects of Great Britain and Ireland. Harley Books, Colchester, UK.
- Kristen, A. and Kanuch, P. (2007) Population, ecology and morphology of Saga pedo at the northern limit of its distribution. European Journal of Entomology, 104: 73-79.
- Council of Europe (1996) Background Information on Invertebrates of the Habitats Directive and the Bern Convention. Part II: Mantodea, Odonata, Orthoptera and Arachnida. Council of Europe Publishing, Strasbourg.
- Demerec, M. (1951) Advances in Genetics. Academic Press, New York.
- Nagy, B. (1987) Vicinity as a modifying factor in a smaller biogeographical units. In: Baccetti, B. (Ed.) Evolutionary Biology of Orthopteroid. Ellis Horwood, Chichester, UK.