Stylops melittae

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Stylops melittae
Female of Stylops melittae in the abdomen of a willow sand bee

Female of Stylops melittae in the abdomen of a willow sand bee

Systematics
Subclass : Flying insects (Pterygota)
Superordinate : New winged wing (Neoptera)
Order : Fan winged (Strepsiptera)
Family : Stylopidae
Genre : Stylops
Type : Stylops melittae
Scientific name
Stylops melittae
Kirby , 1802
Males mating
male

Stylops melittae is a species of the great-winged fan thatparasitizesvarious species of sand bees (Andrena). The males are winged, the adult females remain in their puparium between the abdomen segments of the sand bees.

Way of life

The females of Stylops melittae give birth to large numbers of live primary larvae, which are distributed on flowers. From there they can get together with the pollen into the nesting systems of the sand bees, in which the species specializes. In the nest, the primary larva penetrates the host larva and sheds its skin into the secondary larva, which is exclusively endoparasitic. This wanders around in the host while eating, after a few more moults it settles in the abdomen and breaks with its front body through the skins between two abdominal segments, where it pupates. The exit point is usually between the 4th and 5th, more rarely between the 3rd and 4th abdominal segment.

There are significantly more females (77–92%) than males (8–23%). The females remain in this puparium for their entire life and are sought out here for mating by the males. The winged males leave the puparium after a short phase, only survive a few hours and can therefore only rarely be observed due to their small size. The females release a pheromone (3,5,9-trimethyldodecanal), which attracts the males very effectively. Stylops melittae needs 30–40 days between mating and the birth of the first primary larvae.

Stylops melittae can occur in two generations, but usually only occurs in one generation, so that infested sand bees can usually only be found in the spring months from March to May.

Influence on the type of host

Stylops melittae mainly parasitizes sand bee species that use the flowers in a variety of ways, i.e. are polylectic . Sand bee species that specialize in the flowers of one or a few plant species are less affected. This distribution would not be expected given host specificity. Stylops melittae has a very variable appearance. The proportions of the cephalothorax of the females vary widely and therefore a number of apparently host-specific species have been described at times, which have now been grouped together again into one species. Female sand bees are parasitized far more frequently than males.

Stylopized female sand bees are sterile and resemble their male counterparts in behavior and appearance. The pollen collecting apparatus is reduced, the abdomen is flatter and the color is often reminiscent of male individuals. In addition, the stylopized female bees leave the maternal nest a few days earlier than non-stylopized female individuals, similar to what the healthy male does. The earlier escape of the stylopized females gives the parasite more time for the development of the primary larvae. Stylopized females are no longer active after digging their nests, while healthy females then fly out to care for their offspring. The appearance of the male sand bees, which is more rarely stylopized, is less influenced, but, conversely, is more reminiscent of female animals.

Since the development cycle of Stylops melittae coincides with the death of the host , Stylops melittae is strictly speaking a parasitoid and not a parasite .

Individual evidence

  1. ↑ a b c d e f g Christoph BLEIDORN, Fernand FEITZ, Nico SCHNEIDER, Christian VENNE: On the occurrence of Stylops melittae Kirby, 1802 (Insecta, Strepsiptera) in Luxembourg (PDF; 224 kB) Bull. Soc. Nat. luxemb. 105 (2004) p. 137-142
  2. ↑ a b c M. Kuhlmann: Evidence of mites (Acari) and fan-winged birds (Strepsiptera) associated with bees and wasps (Hymenoptera aculeata) Linzer biol. Article 30/1 69-80 July 31, 1998 (PDF; 818 kB)
  3. ↑ a b c d J. STRAKA, K. REZKOVA, J. BATELKA, L. KRATOCHVÍL: Early nest emergence of females parasitized by Strepsiptera in protandrous bees (Hymenoptera Andrenidae). Ethology Ecology & Evolution 23: 97–109, 2011 (PDF; 359 kB)
  4. ↑ T. Tolasch, S. Kehl, S. Dötterl: First Sex Pheromone of the Order Strepsiptera: (3R, 5R, 9R) -3,5,9-trimethyldodecanal in Stylops melittae Kirby, 1802. Journal of Chemical Ecology 38: 1493 -1503, 2012