Matti Hovi

Extra-pair paternity and male characteristics in the pied flycatcher

The pied flycatcher (Ficedula hypoleuca) is sexually dichromatic with extreme variation in male plumage coloration. The benefit for males of having black plumage is controversial, and few studies have found evidence for a sexual selection benefit of being black rather than brown. However, blacker males may be better able to achieve extra-pair fertilizations (EPFs), which may be an important component of sexual selection. We studied the role of EPFs in sexual selection in the pied flycatcher by establishing a set-up where two males with different back coloration (blacker vs browner) bred simultaneously near each other. DNA fingerprinting analysis revealed that 11% of offspring resulted from EPFs, and that 22% of broods included extra-pair young (EPY) among 36 nests containing 223 nestlings. We found no evidence that browner males suffered more often from EPFs than blacker males. There was no correlation of male or female morphology or age with EPF frequency. However, breeding pairs with low genetic similarity had EPY in their nests significantly more often. Thus we argue that females paired with genetically dissimilar males may try to avoid the effects of extreme outbreeding by seeking extra-pair copulations (EPCs). Alternatively, incompatibility between genetically dissimilar mates may simply expose females to more extra-pair copulations.

Lek Centre Attracts Black Grouse Females

In several lek mating systems, centrally located males enjoy higher mating success than peripheral males. The mechanism behind this pattern, however, has been controversial and a rigorous test of the different alternatives is missing. Here we report that in black grouse Tetrao tetrix, a lekking bird species, central males achieved many more copulations than males in the periphery. Generally, central territories were smaller than peripheral ones, and males were thus more clumped in the centre. A choice experiment in an aviary provided experimental support for females being attracted to densely clustered males, so that males in larger clusters have higher expected average mating success. Thus this mechanism, which was once the common belief for the lekking system but lately has been disregarded, is likely to provide the main explanation for the evolution of lekking in this species.

Properties of food loads delivered to nestlings in the pied flycatcher : effects of clutch size manipulation, year, and sex

Abstract Experimental manipulation of the number of altricial offspring is supposed to modify parental expenditure in birds. In addition to the observed increase in parental feeding rate, it is also possible that the choice of prey or the size of load may change with the changing demand for food. Sexual differences in the provisioning response are also expected, on the basis of earlier studies. We examined the effect of brood size manipulation on choice of prey brought to nestlings and load size in the pied flycatcher. The composition and size of loads differed between years, possibly depending on varying availability of different prey types. Males responded to brood size enlargement by gathering heavier loads, whereas females showed no response. The alteration of load size in males was not explained by a larger number of prey items or mean prey size, but was a combination of these components. It is likely that males also increased their work rate in response to increased food demand at the nest. The absence of response in females might be because they are unable to increase work rate any further, or because food delivery rate in females can not be optimized by changing load properties.

Low male return rate due to clutch enlargements in the pied flycatcher (Ficedula hypoleuca)

Abstract:Increased investment in reproduction during current breeding event may entail future fitness costs. Even though a wide array of both theoretical and empirical work has been devoted to solve the problem of optimal reproductive rate, evidence for costs of reproduction has been equivocal. In the present study we examined the survival of pied flycatcher parents after a clutch size manipulation where we altered clutch size with one or two eggs. We monitored return rates and dispersal of parents during subsequent years after manipulation. An artificial increase in reproductive effort caused lowered return rates of males. Results on breeding dispersal did not support the explanation that observed low return rate was due to differences in dispersal. Thus, it seemed that low return rate of males with increased reproductive effort was due to lower local survival. No survival cost on females was evident, but return rate of females was too low for a proper test. An analysis on reproductive success revealed t...

Black Grouse leks on ice: Female mate sampling by incitation of male competition?

Male-male competition is assumed to limit female choice of mates, but it may also help females to choose the most vigorous males. We studied the mate sampling behaviour of female black grouse (Tetrao tetrix) at spatially unstable leks on ice-covered lakes. In the absence of territories and site-dependence in outcomes of fights, the male dominance hierarchy is very evident on ice. When being courted by dominant males, females frequently tried to approach other males. This was frequently prevented because (1) the courting male and the approached male were involved in physical fight, or (2) the dominant male followed the female and the approached male escaped and avoided contact with him. These behaviours express dominance relationships, and the female behaviour could be considered as incitive. Rank in dominance hierarchy was a significant predictor of male mating success. In this case competition between males and female choice worked in parallel favouring male traits correlated with dominance.

Leucocytozoon muscicapa n. sp. (Leucocytozoidae: Apicomplexa) from the pied flycatcherFicedula hypoleuca (Pallas) (Passeriformes: Muscicapinae)

Leucocytozoon muscicapa n. sp. is described from the pied flycatcherFicedula hypoleuca (Pallas) (Passeriformes: Muscicapinae) from Finland and compared with other leucocytozoids of the family Muscicapidae.