Herb thief
| Herb thief | ||||||||||||
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Herb thief, male |
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| Scientific name | ||||||||||||
| Ptinus for | ||||||||||||
| ( Linnaeus , 1758) |
The herbal thief ( Ptinus for ) is a beetle from the sub- family of spider beetle (Ptininae).
features
Herb thieves are only about three millimeters long and show sexual dimorphism . Both sexes are characterized by long, thread-like antennae and long legs. The males have an elongated shape and are light brown in color, the head and thorax are clearly separated from the abdomen . On the front and rear section of the wing covers are little groups of white flakes. The eyes are arched and wider than the forehead ( frons ). In the middle of the pronotum there is a smooth longitudinal callus, which is bordered on both sides by light, backward-directed hairs. The wing covers are structured with rows of large dots and provided with light, backward-directed hairs.
The females are stockier and the elytra are darker than the pronotum. There are also groups of light-colored scales on the wing covers. The middle of the pronotum is deepened and framed by dense rows of light hairs that touch at the groove-shaped constriction in front of the pronotum base.
Synonyms
- Cerambyx for Linnaeus, 1758
- Bruchus furunculus OF Müller, 1776
- Ptinus germanus Goeze, 1777
- Ptinus humeralis Say, 1835
- Ptinus longipes Rossi, 1794
- Bruchus pulex Goeze, 1776
- Ptinus quercus Boieldieu, 1856
- Ptinus rapax De Geer, 1774
- Ptinus striatus Fabricius, 1792
- Ptinus testaceus Laporte de Castelnau, 1840
Similar species
- Australian thief beetle ( Ptinus tectus )
distribution
Herbal thieves are originally common in the areas of the Palearctic and Nearctic , where temperate climates prevail. They are to be counted among the cultural followers , since they also occur frequently in human dwellings. In the wild they inhabit old trees and bird or hymenopteran nests. Today they are cosmopolitan .
Way of life
The nocturnal animals feed on dried plant and animal substances. For example, they also attack herbal stocks. The resulting damage is usually rather minor. Only the larvae sometimes cause greater damage when they occur in large numbers, especially in grain stores. After a year, the larvae pupate in a small tunnel that is drilled into harder materials. The finished beetle hatches from the pupa.
Breeding of the beetle showed that the female lays an average of 39 eggs, but the number varies widely. The species is one of the rodent beetles that lay few eggs. In the study, eggs were laid for 16 weeks, with a maximum between the third and eighth week with three to six eggs per day. At a humidity of 70 ° it was shown that a temperature of 30 ° C was already so high that the first larval stage did not hatch from the eggs - in contrast to Ptinus sexpunctatus . At the same humidity and a temperature of 23 °, fish meal, wheatfeed (a waste product from the production of wheat flour) and a synthetic agent that had proven itself in the breeding of other rodent beetles were administered as larval food. It was found that the synthetic food initially favored development, but the transformation of the third larval stage into pupae was significantly delayed. From this it was concluded that the synthetic diet was not wholesome. With weatfeed the development was somewhat with unscreened fishmeal, but slower than with sifted fishmeal.
With sifted fishmeal, the following time spans resulted for the individual developmental steps: from oviposition to hatching 16 to 17 days, 1st larval stage 14 days, 2nd larval stage 16 days, 3rd and last larval stage usually 32 days (in special cases another Larval stage inserted for an average of 22 days, and a resting stage could often be observed that the last larval stage was already in the cocoon before pupation and that lasted between 214 and 251 days,) the pupal stage lasted 17 days and passed until it left the cocoon Another 48 days, during which the young beetle reaches sexual maturity. According to this, around 144 days elapse from oviposition to exiting the cocoon, an average of 381 days with a diapause . At alternative temperatures of 20 ° C and 30 ° C (from the first larval stage) the developmental steps took longer and mortality was greater; the optimal temperature is assumed to be slightly above 23 ° C. At lower temperatures, significantly more individuals go through a diapause of the last larval stage in the cocoon.
credentials
- ↑ a b c d e f g h i j Ptinus fur. Fauna Europaea, accessed March 26, 2007 .
- ↑ Jiři Zahradnik, Irmgard Jung, Dieter Jung et al .: Beetles of Central and Northwestern Europe. Parey, Berlin 1985, ISBN 3-490-27118-1
- ^ The Australian thief beetle, Ptinus tectus (Boieldieu, 1856). Lower Saxony State Office for Consumer Protection and Food Safety, accessed on March 26, 2007 .
- ↑ a b RW Howe, B. Sc. Burges, HD Burges: "Studies on Beetles of the Family Ptinidae VI - The Biology of Ptinus fur (L.) and P. sexpunctatus Panzer" in Bulletin of Entomological Research Vol. 42, Issue 3, November 2009, pp 409-511 doi : 10.1017 / S0007485300028893
