The traditional explanation for interspecific plumage colour variation in birds is that colour differences between species are adaptations to minimize the risk of hybridization. Under this explanation, colour differences between closely related species of birds represent reproductive character displacement. An alternative explanation is that interspecific variation in plumage colour is an adaptive response to variation in light environments across habitats. Under this explanation, differences in colour between closely related species are a product of selection on signal efficiency. We use a comparative approach to examine these two hypotheses, testing the effects of sympatry and habitat use, respectively, on divergence in male plumage colour. Contrary to the prediction of the Species Isolation Hypothesis, we find no evidence that sympatric pairs of species are consistently more divergent in coloration than are allopatric pairs of species. However, in agreement with the Light Environment Hypothesis, we find significant associations between plumage coloration and habitat use. All of these results remain qualitatively unchanged irrespective of the statistical methodology used to compare reflectance spectra, the body regions used in the analyses, or the exclusion of areas of plumage not used in sexual displays. Our results suggest that, in general, interspecific variation in plumage colour among birds is more strongly influenced by the signalling environment than by the risk of hybridization.

Of the five known incursions of the highly invasive Red Imported Fire Ant in Australia, two are regarded to have been eradicated. As treatment efforts continue, and the programme evolves and new tools become available, eradication is still considered to be feasible for the remaining Red Imported Fire Ant populations with long‐term commitment and support.

In 2001, the red imported fire ant (Solenopsis invicta Buren) was identified in Brisbane, Australia. An eradication program involving broadcast bait treatment with two insect growth regulators and a metabolic inhibitor began in September of that year and is currently ongoing. To gauge the impacts of these treatments on local ant populations, we examined long-term monitoring data and quantified abundance patterns of S. invicta and common local ant genera using a linear mixed-effects model. For S. invicta, presence in pitfalls reduced over time to zero on every site. Significantly higher numbers of S. invicta workers were collected on high-density polygyne sites, which took longer to disinfest compared with monogyne and low-density polygyne sites. For local ants, nine genus groups of the 10 most common genera analyzed either increased in abundance or showed no significant trend. Five of these genus groups were significantly less abundant at the start of monitoring on high-density polygyne sites compared with monogyne and low-density polygyne sites. The genus Pheidole significantly reduced in abundance over time, suggesting that it was affected by treatment efforts. These results demonstrate that the treatment regime used at the time successfully removed S. invicta from these sites in Brisbane, and that most local ant genera were not seriously impacted by the treatment. These results have important implications for current and future prophylactic treatment efforts, and suggest that native ants remain in treated areas to provide some biological resistance to S. invicta.

A national eradication program for the red imported fire ant, Solenopsis invicta, has been ongoing in Australia since 2001 when the pest was first officially identified in Brisbane, Queensland. Through a range of communication strategies, the program has encouraged the public to report suspect S. invicta and to submit ant samples for identification. There is now a 16‐year dataset of ant specimen submissions from the public and, in the last 5 years, digital ant photograph submissions. Analysis of this dataset shows that, at the end of 2017, the program has processed over 45 000 identifiable ant samples from 41 genus groups from the public in the greater Brisbane region, as well as viewed almost 7000 digital photo submissions. Of these submissions, 8486 were S. invicta samples, with 898 of these originating from a photo. The 10 most commonly submitted local ant genera represent 90% of non‐target ant samples received. Eight of these genera share two or more traits with S. invicta. Since photos were introduced, there has been a reduction in the average yearly non‐target samples received, along with an increase in the proportion of positive detections within public submissions. We conclude that the program's messaging about how to recognise S. invicta has been effective and that photo submissions are a cost‐effective and successful engagement tool. Our study shows that a high level of confidence can be placed on the ability of the public to recognise and report suspect S. invicta and demonstrates again the importance of awareness campaigns in enhancing the probability of passive detection of a target species.

In an effort to improve surveillance capacity for the exotic red imported fire ant, Solenopsis invicta, a lateral flow immunoassay (LFA) was recently evaluated by Biosecurity Queensland staff in Australia. The purpose of the research was to assess the ability of the fire ant LFA to discriminate S. invicta from ants found in Australia and to conduct the first field evaluation of the test. In addition to S. invicta, 36 species of ants, collected mainly from Queensland, were evaluated by the LFA, including species from the Dolichoderinae (n = 7), Formicinae (n = 13), Myrmeciinae (n = 1), Myrmicinae (n = 11), Ponerinae (n = 3) and Pseudomyrmicinae (n = 1) subfamilies. The fire ant LFA test correctly identified S. invicta in every instance. No cross reactivity was observed in the other ant species. Field tests by staff previously unfamiliar with the test resulted in suggestions for improving ant collection and manipulation. The fire ant LFA appears to be suitable for use in Australia for rapid confirmation of potential new detections of S. invicta.