Neither reduced photoperiod, nor female-related social cues, nor increased maternal thermal stress result in a paternally responsive Phodopus sungorus male

Neither reduced photoperiod, nor female-related social cues, nor increased maternal thermal stress result in a paternally responsive Phodopus sungorus male. Physiol Behav [Volume # (Issue #)] 000–000, 2006. —Under laboratory conditions, P. sungorus males are not needed for pup survival and growth and are unresponsive to an experimentally displaced pup. However, males have been found with young pups late in the breeding season, and other laboratories have found evidence for biparental care. Thus, paternal behavior might be expressed in response to relevant social and environmental cues. Reduced photoperiod (from 14L:10D to 12L:12D), increased ambient temperature (from 18 to 23 °C) and pairing with an obligate biparental heterospecific female (to remove behavioral barriers to pup contact) were tested. Although within-animal responsiveness during a standardized pup displacement increased under reduced photoperiod, and pup retrieval occurred more often in the heterospecific pairing, paternal responsiveness scores remained negative, and typical of the species, rather than positive, and indicative of paternal responsiveness. Thus, P. sungorus males did not meet criteria for paternal responsiveness in terms of nest attendance, retrieval rates, or positive paternal responsiveness scores. Pup survival and development were not affected. In spite of their seasonal proximity to pups, there is no evidence that these environmental cues and manipulations are sufficient to result in biparental care.