Successful reproduction by small mammals without access to protein food has not been demonstrated

This article is related to:

Anticipatory responses to pulsed resources: an introduction

In each of the studies that I cited (White 2013) the animals were found to be reproducing prolifically some time before a pulse of food that would not become available until the many young they produced had become independent. And this level of reproduction was in marked contrast to that in the years when there was no such pulse. These researchers therefore concluded that the animals must be using some as yet unknown environmental cue to breed in anticipation of their grown young gaining access to the forthcoming food.

My criticism is that this is not so. These small mammals cannot produce and rear large numbers of young that survive to independence unless their females have access to a source of food that would support such successful reproduction. So, if these rodents are found to be reproducing in this manner, it is because they are, at the time, feeding on such a source of food that can support their breeding. This is not just my contention, it is an undeniable biological fact that Boutin et al. (2013) do not address. Instead they argue that some of the foods I suggested might provide support for such early breeding are not generally available at an appropriate time. They conclude this only from general and indirect evidence, not from direct observation of the animals immediately prior to a mast. Furthermore, they argue this only for squirrels, ignoring the fact that the presence of such an earlier source of additional food is identified for all but one of the other species I discuss.

But, to repeat, even if the rodents could detect a signal that would reliably predict the arrival of food in the future, they could not anticipate its arrival by breeding prolifically before it arrives. They can do this only if they can, at the time, eat food that is sufficient to fuel their reproduction.

In their response Boutin et al. (2013) have not addressed this central problem that I pose. Instead they have devoted their entire comments to defending their original conclusions about squirrels (Boutin et al. 2006) that I have already dealt with (White 2007).

To demonstrate that these several species of animals can breed much more successfully and prolifically ahead of a future pulse of food without prior access to protein food, they must produce experimental evidence of them doing so.

Similarly, they must provide experimental evidence that, as assumed in their model, there are female mammals that can restrain their breeding at a level below that which the available food would support, either in the presence or absence of other females that do not do so.