Immune challenge of female great tits at nests affects provisioning and body conditions of their offspring

Abstract

The trade-off between animal’s parental reproductive effort and survival is still poorly understood. Parental allocation between the workload during breeding attempts and the parents’ own body conditions can be assessed through the offspring quality. Here, I questioned whether the immune responsiveness of female great tits may be considered as a mediator of this trade-off. Specifically, I tested whether (1) the parental reproductive effort decreases, (2) the food composition provided to chicks changes, and (3) whether the nestling immunocompetence and body mass decrease after experimental immunisation. Two populations of great tit Parus major occupying nest boxes were studied in Niepołomice Forest and Krzyszkowice Forest (Southern Poland) in 2011 and 2012, respectively. Three days after hatching, half of the females were challenged with sheep red blood cells (SRBC), while other females were injected with phosphate-buffered saline PBS (control). Six days later, food provided by the parents was collected from nestlings. After another 2 days, the offspring’s body mass was measured and wing web swelling in response to an additional phytohaemagglutinin (PHA) injection. In both years, immunocompetence and in 2012 also body mass in the offspring of SRBC-immunised mothers were lower than in control nestlings, indicating a cost of mounting the immune response in the female. Six days after the start of the female treatment, the number of caterpillars and the volume of food items provided by parents to chicks were higher, whereas the number of spiders was lower in nests with SRBC treatment than in control ones. This might be explained by compensational parental feeding after recovery from the inflammation of a female. Thus, the trade-off between parental effort and survival of parents is mediated by the costs incurred for their immunity and can be assessed by the amount and quality of food provided to the nestlings and the offspring condition.

Fifty years of sheep red blood cells to monitor humoral immunity in poultry: a scientometric evaluation

“…Humoral immunity of wild birds has been influenced by climate changes, migration, season, reproductive performance, and age. These factors have emerged as interesting areas of study for wild avian species ( Kilpimaa et al., 2007 ; Martyka et al., 2011 ; Grzedzicka, 2017 ). Other poultry species were totally assigned in 15 publications that included studying SRBC in ducks (5 studies), pheasants (3 studies), dwarf chickens, geese, guinea fowl, ostrich, partridges, and pigeons (each with 1 study).…”

Impact of rainfall on the offspring PHA‐response and body mass in the Eurasian blue tit

“…The nest boxes were hung on trees approximately 2 m above the ground, with distance of 40–50 m between trees with nest boxes. Habitat in the research area is a deciduous forest dominated by an oak‐hornbeam plant community (see Grzędzicka, for a detailed habitat description). The most common bird species occupying those nest boxes was the great tit, Parus major (about 70 successful nests per year), while the second numerous one was the Eurasian blue tit, Cyanistes caeruleus (about 35–40 successful nests per year).…”

“…Nine days after hatching, food items were collected from the nests. Soft collars made of velcros (Velcro, textile standard, black) intended for clothes were fastened around the necks of all nestlings per nest for 2 hr in the period from dawn until 12 am (see Grzędzicka, for details of this method). Caterpillars and other invertebrates (mainly spiders) were collected from the bills of young birds using tweezers.…”

Ambient temperature impacts the effect of experimental immunisation of Great Tit and Eurasian Blue Tit females on the PHA response of their offspring

“…food access. For example, some previous studies found a direct relationship among the food intake, body mass and PHA response (Yellow-legged Gulls Larus cachinnans: Alonso-Alvarez and Tella 2001; Great Tits: Grzędzicka 2017). However, studies describing the importance of environmental factors for the maternal investment in offspring immunity are lacking.…”

“…Exposure of female Tree Swallows Tachycineta bicolor to sheep red blood cells (SRBC) had no effect on the cell-mediated immunity in their broods (Lozano and Ydenberg 2002). In Great Tits Parus major, the PHA responses of nestlings of SRBC-challenged mothers were lower than in control chicks (Grzędzicka 2017).…”