The Polistes sulcifer wasp is a brood parasitic species, which parasitizes colonies of the paper wasp Polistes dominulus. During an extremely brief time window in the spring, just before the P. dominulus workers have emerged, the P. sulcifer female will invade a P. dominulus nest. Once inside, it will kill or evict the host queen, ensure its cuticle hydrocarbon profile will not lead to its being attacked, and then lay its own eggs. It will rely on the host workers to tend to these.

(Note: I don't know whether it just alters its own hydrocarbon profile, or whether it also alters that of the nest. It's tangential to this question.)

The P. sulcifer wasp needs to time its attacks precisely. If it invades too late, the workers will have emerged and the colony will have a lot more wasps to defend it. If it invades too soon, there will not be enough host workers emerging to tend to its brood, especially if the host queen has not laid many eggs. P. sulcifer itself does not have a worker caste, and so is entirely reliant on host workers.

Research published in 2004 (paywalled, unfortunately) showed that the parasite wasp eggs took an average of 5 days to hatch after being laid, with the minimum observed being 3 days. This was in marked contrast to the host eggs, with average time 8.6 days in an unparasitized host colony, and 9.1 in one which was parasitized. Likewise, the parasite larval stage was much shorter, lasting an average of 9.8 days as opposed to 16.6 for host larvae in a parasitized nest (14.8 in an unparasitized colony) and the pupal stage also slightly shorter.

The parasite larvae were able to attract more attention from the workers than the host larvae - including being fed more often - which would appear to offer an explanation for the faster larval development and shorter larval/pupal stages. But this does not explain the shorter egg stage. Rapid development is clearly advantageous in terms of maximising the number of offspring produced, so a shorter egg stage is advantageous to the parasite, but the mechanisms behind this short incubation period are not known.

In the famous example of an avian brood parasite, the cuckoo, the parasite eggs also hatch more rapidly than the host eggs. This is, at least in part, because the female cuckoo holds the egg in her oviduct for an additional 24 hours prior to laying, at a higher temperature than an egg being incubated in the host nest. This gives the cuckoo egg the equivalent of a 30 hour head start on the host eggs.

In the aforementioned 2004 research paper, it was speculated that the wasp might use a similar mechanism, but this was not known, and no research into this had been carried out. A later 2006 paper also stated that no information was known about this, and I have been unable to find any further research on the topic.

Has there been any subsequent research into how P. sulcifer has been able to ensure its eggs hatch abnormally soon after being laid?

Sources - paywalled:

Cervo, R., Macinai, V., Dechigi, F., & Turillazzi, S. (2004). Fast growth of immature brood in a social parasite wasp: a convergent evolution between avian and insect cuckoos. The American Naturalist, 164(6), 814-820.

Ortolani, I., Turillazzi, S., & Cervo, R. (2008). Spring usurpation restlessness: a wasp social parasite adapts its seasonal activity to the host cycle. Ethology, 114(8), 782-788.

Sources - non-paywalled:

Cervo, R. (2006, January). Polistes wasps and their social parasites: an overview. In Annales Zoologici Fennici (pp. 531-549). Finnish Zoological and Botanical Publishing Board.

Cervo, R., Dani, F. R., Cotoneschi, C., Scala, C., Lotti, I., Strassmann, J. E., ... & Turillazzi, S. (2008). Why are larvae of the social parasite wasp Polistes sulcifer not removed from the host nest?. Behavioral Ecology and Sociobiology, 62(8), 1319-1331.

Other sources: Davies, Nick B. (2015). Cuckoo: Cheating by Nature. Bloomsbury. ISBN 978-1-4088-5658-1.



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