The ‘big spenders’ of the steppe: sex-specific maternal allocation and twinning in the saiga antelope

Abstract

Reintroductions are important tools for the conservation of individual species, but recently more attention has been paid to the restoration of ecosystem function, and to the importance of carrying out a full risk assessment prior to any reintroduction programme. In much of the Highlands of Scotland, wolves (Canis lupus) were eradicated by 1769, but there are currently proposals for them to be reintroduced. Their main wild prey if reintroduced would be red deer (Cervus elaphus). Red deer are themselves a contentious component of the Scottish landscape. They support a trophy hunting industry but are thought to be close to carrying capacity, and are believed to have a considerable economic and ecological impact. High deer densities hamper attempts to reforest, reduce bird densities and compete with livestock for grazing. Here, we examine the probable consequences for the red deer population of reintroducing wolves into the Scottish Highlands using a structured Markov predator-prey model. Our simulations suggest that reintroducing wolves is likely to generate conservation benefits by lowering deer densities. It would also free deer estates from the financial burden of costly hind culls, which are required in order to achieve the Deer Commission for Scotland's target deer densities. However, a reintroduced wolf population would also carry costs, particularly through increased livestock mortality. We investigated perceptions of the costs and benefits of wolf reintroductions among rural and urban communities in Scotland and found that the public are generally positive to the idea. Farmers hold more negative attitudes, but far less negative than the organizations that represent them.

Mother traits and offspring sex in two threatened gazelle species in captivity

“…In gazelles, as in other polygynous mammals, the variance in male reproductive success exceeds that of females (Clutton-Brock et al, 1982, 1986Hewison et al, 1999;Wolff, 1988;Knut et al, 2007) and this success depends on calf weight and/or adult body size (Clutton-Brock and Iason, 1986, Landete-Castillejos et al, 2005) because they are related to their fighting ability (Knut et al, 2007;Kühl et al, 2007). Inbreeding has been shown to influence body size in domestic, captive and laboratory animals as well (Charpentier et al, 2006;Coltman et al, 1998;Fredrickson and Hedrick, 2002;Wright et al, 2008).…”

Sexual conflict in twins: male co-twins reduce fitness of female Soay sheep

“…humans: James 2002; domestic sheep: Beatty 1956; Burfening 1972; but see Avdi & Driancourt 1997; and Saiga antelope: Kühl et al . 2007).…”

Differential investment in twin offspring by female pronghorns (Antilocapra americana)

“…This mass differential could be a physiological side effect with no adaptive value (Marshall and Uller 2007). It also could result from interactions between fetuses in utero (Korsten et al 2009;Kühl et al 2007); such an explanation seems plausible for pronghorns, which are unusual in producing multiple embryos that are reduced to 2 before birth via sibling competition (O'Gara and Yoakum 2004). However, the mass differential was associated with higher survival for both co-twins and consequently a higher fitness for the mother, so perhaps it has an evolutionary basis.…”