Concerning spiders, is there any research on whether web-building is an inherited behavior, or if it must be observed and learned? e.g. Has anyone hatched spider eggs in isolation and observed whether the descendants still know how to build a web?
Spiders’ ability to weave webs is a classic example of an innate or instinctual behavior. They do not learn to make webs.
The earliest English-language scientific publication that I can find to back this claim is Porter 1906 1, which focuses on variation in the webs of Orb-weaving spiders:
The web of the Orb-weaving Spiders has long been one of the classical examples of animal instinct. It is so definite and complex, and yet so frail a structure and must be rebuilt so often under varying conditions that, a priori, we should expect it to furnish one of the best of fields for the study of the variation of instinct. If the cell of the Honey-bee varies so that, according to Prof. Wilder (73, pp. 654,655), who quotes Prof. Wyman in this connection, there may be a gain or loss of one cell in ten, then from a knowledge of the differing conditions under which the spider works, together with the frailty of the web as compared with the cell, we have as much, and even more, ground for thinking that even greater variation will be found here.
In his review of the literature, Porter directs readers to Menge's 1843 work About the way of life of the arachnids 2 for an overview of spider physiology and behavior, as well as works by Wagner 3,4 as specific references for spider instinct and its variation. Unfortunately, these works are not written in English, so I cannot verify their claims.
- Porter, J. P. 1906. The habits, instincts, and mental powers of Spiders, Genera, Argiope and Epeira. The American Journal of Psychology, 17(3), 306–357.
- Menge, A. 1843. Über die Lebensweise der Arachniden. Neuste Schr. Naturf. Gessell. IV, Danzig.
- Wagner, W. 1897. L'Industrie des Araneina. Mem. de l'acad. Imp. des Sci. de St. Petersburg. Tome, XLII, No. II, pp. 269.
- Wagner, W. 1900. L'arraignde aquatique (argyroneta aquatica Cl.) son industrie et sa vie. Materia de psychologie comparde. Bull. Soc. Moscou, pp. 61-169.
For many species the mother abandons the eggs after laying them and there is no maternal care (sometimes the mother dies after laying eggs, so really no possibility of maternal care). Paternal care is generally completely lacking as well (and sometimes the father is expected to die before hatching). And many of those species are solitary, so not learning from other unrelated spiders. So for those spiders web weaving is obviously innate.
As a bonus, this includes some species of the most dramatic web weavers, orb weaving spiders.
(Note that other spider species are fantastic mothers with a prolonged period of child-rearing, so I guess it's possible that it's learned in those species, but Occam's razor suggests that it's innate in all spiders.)