Mr John Gould

The most well-known use of silk among spiders is the formation of webs to capture flying prey. However, spiders have evolved many different foraging strategies involving silk, including the capture and subsequent manipulate of prey prior to consumption. Herein, I report on the use of silk lines by a long-jawed spider from the Tetragnatha genus to move a large prey item vertically through the air. Field observations revealed a long-jawed spider attaching multiple silk lines across the body of an adult dragonfly that had recently emerged from its final moult and attaching these threads to overlying vegetation to incrementally haul the prey item from the surface of a waterbody. My observations suggest that some Tetragnatha spiders are able to move large prey items that are much heavier then themselves using a series of silk lines that allow lift to be accomplished in a gradual and controlled manner. This is an interesting finding, given that other individuals from the same population were using web structures to passively catch much smaller, flying prey. This indicates that some Tetragnatha spiders not only participate in the mobile pursuit of prey but that they possess multiple foraging strategies that may allow them to exploit a larger number of prey types.

For oviparous animals such as amphibians, the presence or absence of conspecifics can influence site selection, with each life history stage potentially influencing the decision-making process in a different manner. In the present study, we tested the effect of conspecific life history stage on oviposition site selection in the sandpaper frog, Lechriodus fletcheri. We quantified preferences for spawning in pools that were unused by conspecifics, as well as pools with conspecific spawn or tadpoles present, or both. The study included two ecological contexts: a system of naturally occurring breeding pools and a field experiment with 40 artificial pools that controlled for habitat variation. Mothers preferred to oviposit in pools that already contained conspecific spawn, despite the likelihood of intense resource competition upon offspring hatching. This could be due to the potential benefits obtained by providing offspring access to a significant nutrient supply upon hatching via cannibalism of conspecific tadpoles and might be an important adaptation for completing tadpole development in highly ephemeral and resource-limited pools prior to desiccation. In contrast, mothers avoided ovipositing in pools with conspecific tadpoles, a probable adaptation to avoid their own offspring from becoming victims of cannibalism themselves prior to hatching. Such nuances in the effect of conspecific presence on offspring survival highlight the often complex decision-making process that amphibians need to make when selecting oviposition sites, as well as the influence cannibalism can have on the evolution of reproductive behaviour.