Promoted
The end and the beginning
A moment of simultaneous fascination and sadness upon seeing this phenomenon for the first time. Such is the natural world and all its many convoluted, connected pathways.
I believe this is a catalpa sphinx moth caterpillar that has been parasitised by a braconid wasp...seen here attached to the caterpillar are the wasp pupae, or cocoons that have finished feeding and are metamorphosing into adults.
I noted that the caterpillars (although often stunted and slow to react), looked alive with their extra baggage of cocoons - but I learned that the damage had been done and their days were numbered.
Body length of caterpillar 50mm
The Catalpa Sphinx is a hawk moth of the Sphingidae family.
Similar species: Moths And Butterflies
By Ruth Spigelman
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Uploaded Jan 15, 2019. Captured Aug 2, 2015 15:20 in 685-A National Pike West, Brownsville, PA 15417, Brownsville, PA 15417, United States.
comments (9)
This Catalpa Sphinx (Ceratomia catalpae) caterpillar has been parasitized. It is covered in the cocoons of a braconid wasp, most likely Cotesia congregata. The relationship between the caterpillar and endoparasitic wasp is as complicated as it is fascinating. Catalpa trees are the sole plant hosts for the catalpa sphinx caterpillar. The caterpillars sequester high concentrations of iridoid glycoside catapol from their host plants. This makes them taste gross, thus protecting them from a variety of predators. However, this chemical defense doesn't stop wasps from parasitizing the caterpillars! Instead, having a chemically-defended host may benefit the wasps as it provides their eggs with a safe haven in which to develop. Chemical defense backfires for the catalpa sphinx!
Endoparasitic wasps, such as Cotesia congregata, lay their tiny eggs inside a caterpillar—using it as a living incubator. To put it in perspective, the wasps generally inject at least 65 eggs that are each 0.12 mm in size into a single caterpillar! The eggs hatch and the larvae squirm around inside their host, eating it alive. When they are ready to pupate, they tear through the caterpillar's cuticle and spin cocoons, which they attach to the caterpillar's back. Surprisingly, the caterpillar is usually still alive at this point because the wasp larvae are careful to only feed on nonessential tissues and hemolymph (blood); although, the caterpillar's death is certainly inevitable.
While this process is not simple, it is about to get more complicated. It would be unfortunate for the wasps if their caterpillar host completed its own development before the wasp larvae completed theirs. So, when the wasp mother initially injects her eggs into the caterpillar host, she squirts some venom in as well. This venom, along with teratocytes from the wasp eggs, arrests the caterpillar's development. In addition, the wasp relies on a virus to suppress the caterpillar's immune system so it doesn't reject and attack the wasp eggs. As an added benefit, the virus also prevents the caterpillar from storing proteins for its own use; instead, nutrients are kept in the hemolymph for use by the wasp larvae. Where does this virus come from? The viral genes are part of the wasp's genes! The female wasps produce the virus. Without the wasp, the virus would not exist, and without the virus, the wasp eggs would die. They are mutually symbiotic. There are so many factors that have to be perfect in order for wasps to develop inside their caterpillar hosts! The intricacies of nature are mind-blowing! {Spotted in Pennsylvania, USA by JungleDragon user, Ruth Spigelman} #JungleDragon Posted 6 years ago
Insects have many unique and distinct differences from other animals. For example, they generally have very short life cycles that necessitates a lack of exhibited pain as we know it. Traditional pain would hinder their instinctive short feeding and reproductive life cycle. Insects generally react very differently than higher life forms in response to deleterious events. They do not exhibit protective behavior towards injured body parts; nor do they stop mating and eating even in the presence of severe injuries. For example, tsetse flies ignore extreme injury and continue to feed even if half-dissected. Further, locusts have been observed to continue to feed while being eaten by mantises. In general, insects do not react to treatment that would certainly cause severe pain in other life forms (see Eisemann et al. 1984). So, there is solid evidence to believe that generally insects don't feel pain. (Animal Sentience 2016.111: Merker on Klein & Barron on Insect Experience Posted 3 years ago