The ecological challenge of immunocontraception: editor's introduction

1, The problems of vertebrate pests are greater now than ever before, with vertebrate control constrained by problems of humaneness. scale and environmental impact. However, immunocontraception involves a conceptually ideal solution. Although not intrinsically novel, its delivery in baits or by a self-spreading vector and its effectiveness in pest control, are now; the focus of growing international interest. 2, Major ecological questions correspond to the two forms of delivery: baits and vectors. First, given an effective immunocontraceptive, inserted into a bait and eaten by a pest, would the resulting level of sterilization in the population effectively suppress densities? Secondly, given that the immunocontraceptive agent can be inserted into a microparasitic or macroparasitic infective vector, would the modified vector persist at sufficient prevalence in the host population, and hence suppress densities to the required extent? 3, The papers published in this Special Profile focus on behaviour following sterilization or they model the likely impact of viral-vectored immunocontraception. They highlight advantages and disadvantages of immunocontraception and some general, novel and specific issues. These include the possibility of behaviourally mediated population responses to fertility control; the possible advantages of a mixed baiting and vector strategy; the competitiveness of a modified vector; the appropriateness of immunocontraception for controlling invasive vertebrates on islands; and the need for a 'pay-off' methodology for assessing genetic modifications against alternatives. 4, The findings offer significant benefits for management and policy: they will inform decisions on whether to pursue immunocontraception as a control option: and they provide evidence about efficacy and risk in applications to release genetically modified vectors. 5, Although many of the problems in developing immunocontraception technology are biotechnological, questions about the effectiveness of immunocontraceptive pest control are ultimately in the domain of ecologists.