Stabby bugs: Assassin bugs (Reduviidae)
Above: Stuff of nightmares (if you are an insect). Yellow assassin bug nymph (Cosmolestes picticeps).
In my opinion, assassin bugs (minus the blood-sucking Triatominae) are some of the most useful bugs to have in the garden. As their name suggests, assassin bugs are ferocious carnivores in the insect class. They tend to be general predators rather than specialised predators, meaning they feed on a wide array of smaller insects and arthropods from aphids to beetles to even ants. They are also quite mobile; adults have well-developed wings which make them pretty good fliers.
Assassin bugs belong to the suborder Heteroptera, or true bugs, which also consists of leaf-footed bugs (Coreidae), stink bugs (Pentatomidae) and flat bugs (Aradidae), among many others. The Heteroptera are easily identified by their proboscis or sucking mouthpart, which is often less obvious in other Hemipterans (the order which contains Heteroptera as well as other suborders) such as aphids and leafhoppers. Identification among the Heteropterans can get a little trickier, but in general, the assassin bugs of the family Reduviidae can be distinguished by looking out for the short, hooked proboscis, and long heads. The leaf-footed bugs are occasionally mistaken for assassin bugs, but the former tend to have long proboscis, a less lengthy head and thicker antennae than the latter.
Many assassin bugs are capable of inflicting a painful bite on humans, and thus should be respected as such. The species that feed on insects are not known to transmit any human diseases, but the Triatominae assassin bugs, also known as kissing bugs, are known to transmit the deadly Chagas disease in South America. Fortunately, no such cases have been reported in Singapore.
The assassin bug truly is a living nightmare for smaller insects like aphids and ants. These killer bugs stab their unwitting victims with their hooked proboscis, and proceed to suck the contents of their stunned prey, leaving behind an empty lifeless husk. They remind me of the zompires from the TV series The Strain, minus the reanimation part.
In my experience, the most commonly encountered assassin bug in Singapore is the Yellow assassin bug, Cosmolestes picticeps. This common assassin bug can be found in the shrubby and forested areas throughout the island and may even fly into human habitation occasionally. I have observed them in parks, as well as the Central Catchment Nature Reserve. I have seen a nymph eating a beetle larva, as well as an adult feeding on nectar, as supplementary nutrition. Carnivorous insects like assassin bugs and lacewings are known to feed on nectar for a quick, rich sugary meal. Other assassin bugs I have come across in Singapore include Ricolla sp., as well as the millipede assassin bug, Scadra sp..
I am very eager to look for more species of Reduviidae in Singapore, as I know there are a lot more of these stabby bugs out there. A particularly interesting one is Acanthaspis petax, the ant assassin bug known to carry around the empty husks of its victims on its back to defend itself from potential predators like jumping spiders.
Above: Ricolla sp.
Below: An adult Yellow assassin bug (Cosmolestes picticeps).
If you are a passionate aphid-hater, as with most gardeners and farmers, you will want these fascinating creatures in your garden. So how does one attract them to the garden? For one, planting loads of nectar-rich flowering plants to serve as an alternative food source will probably prove irresistible to them stabbers. Next, not spraying pesticides and herbicides will probably help encourage them to stay as well. Perhaps most importantly though (and tying to the previous two points), having a constant food supply, which means resisting the urge to kill off all the aphids and other prey, will help to keep them in your garden or farm.
Above: What's worse than a non-flying assassin (nymph)? A flying vampire! This newly emerged adult yellow assassin bug still has its exuviae or moult close to it. It will never moult again, as with most adult insects.