Do swallows (Hirundo daurica) use the visual cue of hatchling down‐feathers to discriminate parasite alien nestlings?

Abstract

Egg recognition is a variable but common anti‐parasitism defense among different species of birds with brood parasites. In contrast, nestling recognition is rare. Very few studies have found nestling recognition in brood parasite hosts and determined the rejection mechanism behind this behavior. Hosts may use the number of hatchling down‐feathers to reject parasite nestlings. We tested whether hatchling down‐feathers is a visual cue for the red‐rumped swallow, a host that can recognize and reject parasite nestlings. Our results indicated that red‐rumped swallows do not recognize foreign nestlings based on hatchling down‐feathers. The closed nest structure and hatchling morph may explain the absence of such a mechanism. None of the rejection mechanisms found in previous studies could explain the nestling recognition in swallows. Olfactory cues, tactile cues, or other visual cues, except for single nestling or hatchling down‐feathers, may provide nestling recognition in red‐rumped swallows. More study is needed to evaluate these possibilities.

Density‐dependent changes of mating system and family structure in Brandt's voles (Lasiopodomys brandtii)

“…There are three plausible explanations. First, the observed extra‐group maternity may be similar to the intraspecific brood parasitism in birds (Wang et al, 2020; Yang et al, 2020), which would maximize the fitness of females. Female voles may put their lactating pubs in the other families, resulting in “litter parasitism.” These “parasite litters” may face a high risk of killing by the host females because voles are sensitive to odors, and they can easily distinguish their pubs from the others.…”

“…There are three plausible explanations. First, the observed extra-group maternity may be similar to the intraspecific brood parasitism in birds (Wang et al, 2020;Yang et al, 2020), which would maximize the fitness of females. Female voles may put their lactating pubs in the other families, resulting in "litter parasitism."…”

Personality, recognition cues, and nest sanitation in obligate avian brood parasitism: what do we know and what comes next?

“…Although ABP has been the subject of numerous studies since Darwin’s time, the personalities of the parasites and hosts have not been taken into account much in previous studies. As to the recognition cues, which are used by the hosts to discriminate parasites, have received more studies, but mostly focused on egg recognition that there is still a dearth of exploration to the nestling recognition ( Wang et al 2020 ). Furthermore, nest sanitation, a behavior that is similar in pattern to egg rejection, was proposed to be a pre-adaptation of the latter in hosts ( Rothstein 1975 ); however, the conclusions from previous studies were mixed.…”