The teratocytes secrete hormones which work in tandem with the virus and the wasp venom to arrest the development of the host.

Dissection of post-emergence caterpillars revealed three categories of remaining larvae:[4] This insect has the shortest flagellated spermatozoa in animals, being 6.6 μm long (nucleus and flagellum), 8800 times shorter than the longest ones (Drosophila bifurca).

Phagocytic cells will clean up the debris, and the virions will be injected into the host along with eggs and venom upon oviposition.

[9] However, most hosts weigh less than unparasitized caterpillars[9] and after they reach the fifth instar their feeding rate will reduce, causing their weight to decline significantly.

[10] The infected host will sometimes reach a supernumerary sixth instar[10] if a high number of parasite larvae are present inside it.

Sixth-instar caterpillars below the threshold size for pupation at the end of the fifth instar are killed through parasite emergence.

[12] Approximately 8 hours before the wasp larvae emerge, the parasitized caterpillar's food consumption significantly declines.

[9][14] Without human intervention, the reduced appetite and locomotion are both permanent - the caterpillar will never return to its normal behaviour, even after the parasites have emerged.

Other proteins found to increase in neurosecretory cells in both starved and parasitized larvae are: bombyxin, allatostatin, allatotropin, diuretic hormone, FMRFamide, and proctolin.

[10] The polydnavirus disallows these proteins from being released into the nervous system, instead causing them to accumulate in neurosecretory cells.

Specifically with PTTH, due to the accumulation, is not released in sufficient amounts to stimulate the synthesis of ecdysteroids by the prothoracic glands, which will prevent subsequent development of the larvae.

These hormones also allow the parasitized larva to survive longer without food or water, due to a slowdown of diuresis (urine production) and gut purge.

Starved larvae can also ultimately molt and pupate if they are large enough, but this can be explained by the temporal difference in the beginning of accumulation.

Within 24 hours of oviposition, the host is unable to encapsulate any antigen which enters its body, preventing it from attacking the wasp larvae.

[12] From an evolutionary standpoint, it is beneficial for the wasp larva that the host should recover its resistance to external pathogens without regaining the ability to destroy the parasite.

[2] Researchers were able to counter the decline in locomotion by surgically removing the host's supraesophageal ganglion (brain) during day 4 of the fifth instar, prior to parasite emergence.