The effects of seed detectability and seed traits on hoarding preference of two rodent species

Abstract

Seed traits play an important role in affecting seed preference and hoarding behaviors of small rodents. Despite greatly affected by seed traits, seed detectability of competitors represents pilfering risks and may also modify seed hoarding preference of animals. However, whether seed traits and seed detectability show consistent effects on seed hoarding preference of animals remain largely unknown. Here, we explored how seed traits and seed detectability correlate with seed hoarding preference of Leopoldamys edwardsi and Apodemus chevrieri in a subtropical forest. Despite the effects of seed coat thickness and caloric value on hoarding preference of L. edwardsi, we detected no significant effects of other seed traits on hording preference of the 2 rodent species. There was no correlation between larder‐hoarding preference and inter‐ or intra‐specific seed detectability of L. edwardsi; however, seed detectability of L. edwardsi was negatively correlated with its own scatter‐hoarding preference. Although scatter‐hoarding preference of A. chevrieri was not correlated with inter‐ and intra‐specific seed detectability, larder‐hoarding preference of A. chevrieri was positively correlated with intra‐specific seed detectability. Our study may provide evidence that intra‐specific seed detectability rather than seed traits and inter‐specific pilfering risks play an important role in modifying seed hoarding preference of rodents.

Seed removal, seed dispersers, and the allocation of tissues in Myrtaceae seeds

“…However, it is possible that the size range of these species, neither small enough to escape the attention of rodents nor large enough to mechanically constraint their exploitation by the smaller rodents (Vieira et al, 2003), would make unimportant any possible gain in protection provided by a thicker seed coat. Large‐seeded, rodent‐dispersed seeds, on the contrary, are under a different selective scenario since it is well‐known that better protected seeds have a greater chance of being cached rather than eaten immediately by rodents (Chang & Zhang, 2014; Vander Wall, 2010; Wang & Yi, 2021). Therefore, to invest energy in allocating a greater proportion of seed coat as the seed gets larger is to increase the plant own investment in large seed reserves, both contributing to the survival of the embryo.…”

“…Particularly interesting are seeds dispersed by agents that play a dual role, such as rodents that can act either as predators, when they eat the seed's endosperm and kill the embryo, or as dispersers, when they hoard and abandon seeds, occasionally promoting their germination and subsequent recruitment (Van der Pijl, 1982). The balance between mutualism and predation depends on rodent and seed traits, such as size (of both rodents and seeds), seed hardness and nutrient content, the presence of secondary metabolites in seeds that impair seed consumption, and the amount of food available in the environment (Chang & Zhang, 2014; Wang & Yi, 2021). In fact, the size of rodent species and seeds are particularly important in this relationship, affecting all the steps of the decision‐making process of scatter‐hoarding rodents when dealing with seeds.…”

Plant hormones mediate the interaction between oak acorn germination and rodent hoarding behaviour

“…Leopoldamys edwardsi Thomas is the dominant scatter‐hoarding species in the study area (Zhang et al ., 2008; Yang et al ., 2018; Wang & Yi, 2022). We captured L. edwardsi near the study plots using wire live traps (30 × 13 × 12 cm) baited with fresh chestnuts (Yang et al ., 2022b).…”

Conflicting selection pressures on seed size and germination caused by carnivorous seed dispersers

“…Seed predators (i.e. rodents and insects), which are granivorous, generally prefer large seeds that offer a better cost-benefit balance (Wang & Yi 2022). Some frugivores, however, exert opposite choices (Janzen 1984); this has been evidenced for birds (van Leeuwen et al 2012), ungulates (Chen & Moles 2015), and monkeys (Stevenson et al 2005), and their gut transit could enhance the rate of germination of these small seeds (Torres et al 2020).…”

“…Seed predators (i.e. rodents and insects), which are granivorous, generally prefer large seeds that offer a better cost‐benefit balance (Wang & Yi 2022). Some frugivores, however, exert opposite choices (Janzen 1984); this has been evidenced for birds (van Leeuwen et al.…”