Robber Fly (Assassin flies): Voracious Predator of Insects

Robber Fly (Assassin flies): Voracious Predator of Insects 

       
       As we all knows flies as being particularly badass, annoying and filthy. But there is actually one kind of fly that's just as voracious of a predator as any savage jungle cat or surfer-mangling shark. They are called robber flies (Assassin flies).


  



















According to Torsten Dikow, curator in the entomology department at the Smithsonian’s National Museum of Natural History, assassin flies are “aggressive, visual predators that perch on vegetation and rocks to look for insects flying by. Once an assassin fly spots its prey, it follows and attacks it in flight by grabbing the insect with its legs, biting it on its back or side, and injecting it with venomous saliva.” Venomous saliva of robber fly kill the prey quickly. Then the fly take its prey to safe place with strong, bristle legs to eat at its leisure. The saliva not only kills the insect, it liquefies inside and sucks up. Then leave the empty carcass behind and wait for more prey.

    

The venomous toxin composition of robber flies are yet to decode and have not published any comparison with venom of other arthropods like scorpions or even other animals like snakes or jellyfish.  

“Assassin flies have mixed impact on agriculture”

Adults prey on a variety of arthropods and considered to be beneficial insects for different varieties of crop cultivations. However, they are dangerous for apiculture, as they hunt and feed on bees, they can easily enter to beehive and can adversely affect their population.

Photo Courtesy: Subasa Bishwal

The Small Blue

The Small Blue: A Beautiful Tiny Creature of Nature

“Everyone is like a butterfly, they start out ugly and awkward and then morph into beautiful graceful butterflies that everyone loves.”

-Drew Barrymore

The Small blue (Cupido minimus) belongs to the family Lycaenidae, found in small groups of a dozen. The species is mostly found in grassland and woodland edges. Both sexes nectar mainly on leguminous plants. It is not particularly blue despite its common name. The female is mostly dark brown but the male has some bluish suffusion at the base of its upper wings. The species is mostly found in Europe, Asia, Siberia, Russia, Mongolia.     

The small blue lay their pale greyish-blue eggs individually on the flowers. All over the flower head, they rub their abdomen to produce a scent which prevents from other females to lay their egg on the same flower. Because one flower can support only one larva.  Unfortunately, the scent evaporates after a day or two, so several eggs laid by the same or different female but only single larvae survive.

After 10 days the larvae emerge out and burrows into the flower which feeds on anthers and seeds. The fully grown larvae leave the plant and settle down in the ground and spend its winter. Most larvae pupate the following May and produce butterflies in June, but some remain in diapause and emerging in August of the following year

This species of butterfly has an interesting ant-attracting organ, which deters other insects from attacking the species.