The diversification of Heliconius butterflies: what have we learned in 150 years?

Research into Heliconius butterflies has made a significant contribution to evolutionary biology. Here, we review our understanding of the diversification of these butterflies, covering recent advances and a vast foundation of earlier work. Whereas no single group of organisms can be sufficient for understanding life's diversity, after years of intensive study, research into Heliconius has addressed a wide variety of evolutionary questions. We first discuss evidence for widespread gene flow between Heliconius species and what this reveals about the nature of species. We then address the evolution and diversity of warning patterns, both as the target of selection and with respect to their underlying genetic basis. The identification of major genes involved in mimetic shifts, and homology at these loci between distantly related taxa, has revealed a surprising predictability in the genetic basis of evolution. In the final sections, we consider the evolution of warning patterns, and Heliconius diversity more generally, within a broader context of ecological and sexual selection. We consider how different traits and modes of selection can interact and influence the evolution of reproductive isolation.

Domestic iron burns in children: a cause for concern?

The case notes of 26 children with contact thermal burns to the hand who were treated in the Burn Unit at Stroke Mandeville Hospital as inpatients during the period 1987-92 have been reviewed. The burns were found to be caused by a variety of injuring agents, although the domestic iron was the single commonest cause accounting for 46 per cent of cases. Mechanisms of iron injuries were variable although leaving a hot iron on the floor or on a low table were identified as being two important causes. Fifteen children (58 per cent) underwent either primary or tangential excision of the burn skin and grafting. The majority of the children had a satisfactory outcome, although five children (19 per cent) developed hypertrophic scars. The results of this study demonstrate the relatively high incidence of domestic iron burns as a causative factor for contact hand burns in children. Parental vigilance and leaving a hot iron in a secure place are two factors which will help to reduce the incidence of this potentially serious injury.

PCR analysis of Pasteurella multocida isolates from an outbreak of pasteurellosis in Indian pigs.

An outbreak of pasteurellosis with high mortality was recorded in indigenous pigs in India. The presence of Pasteurella multocida in samples collected from dead pigs was detected by smear examination and isolation, and later by P. multocida specific polymerase chain reaction (PM-PCR). P. multocida was detected in all the samples collected from dead pigs, with nine strains ultimately isolated. All the isolates were positive by PM-PCR. Six isolates showed CAPA and three were of CAPD capsular types. All the isolates were negative for toxigenic gene (toxA). The isolates were sensitive to oxytetracycline, doxycycline, gentamycin, erythromycin, ampicillin, amoxycillin, chloramphenicol and enrofloxacin and resistant to sulphadiazine and cloxacillin. The PCR assays used in this study have been shown to be useful diagnostic tools for P. multocida detection and characterization.