New data on the aphid (Hemiptera, Aphididae) fauna of New Caledonia: some new biosecurity threats in a biodiversity hotspot

Thirty-three species of aphids are now established in New Caledonia. All species appear to have been introduced accidentally by human activity in the last century. Here, 17 aphid species are recorded for the first time: Aphiseugeniae, Aphisglycines, Aphisodinae, Aulacorthumsolani, Brachycaudushelichrysi, Cerataphisorchidearum, Greenideapsidii, Hyperomyzuscarduellinus, Hysteroneurasetariae, Lipaphispseudobrassicae, Micromyzuskatoi, Myzusornatus, Pentaloniacaladii, Rhopalosiphumnymphaeae, Rhopalosiphumrufiabdominale, Schizaphisrotundiventris, and Tetraneurafusiformis. Thirteen more species are also more or less regularly intercepted at the borders through biosecurity surveys, without further establishment. This demonstrates that aphids represent a major biosecurity threat, including a threat as potential plant virus vectors. The reinforcement of biosecurity is a priority for such biodiversity hotspots, from the perspectives of both agriculture and the native environment. Prioritisation and promotion of local development of vegetable and fruit production, rather than their risky importation from abroad, is desirable. Such an approach also should be promoted and extended to other Pacific islands, which all share the lack of native aphid fauna and their associated plant disease vector risks.

Non-destructive DNA extraction methods for entomophagous insects with emphasis on biological control

One of the major challenges in molecular analysis of arthropods, especially for natural enemies of insect pests, is the intact preservation of the specimens to be integrated into entomological collections. However, most of the DNA extraction protocols involve maceration of the tissue, avoiding the preservation of the original specimen. Two general methods were adapted into non-destructive DNA extraction protocols, DNeasy® Blood & Tissue Kit (A) and the CaCl₂ lysis buffer method (B), while the potential of the method with the alkaline lysis buffer (HotSHOT; C) was evaluated for the first time on insect specimens. These protocols were assessed for the recovery of DNA from Ceraeochrysa valida, Tamarixia radiata, and Hippodamia convergens. Photographical records showed that morphological features of the specimens were preserved after the DNA extraction process. COI fragments were successfully amplified with method A (100%), B (77%), and C (88%), respectively. We conclude that these non-destructive DNA extraction methods avoid the destruction of tissue and preserve the original insects and their morphological characteristics for future reference.

Three Salmonella enterica serovar Enteritidis bacteriophages from the Siphoviridae family are promising candidates for phage therapy

Salmonella is a common and widely distributed foodborne pathogen that is frequently implicated in gastrointestinal infections. The emergence and spread of Salmonella strains resistant to multiple antibiotics poses a significant health threat, highlighting the urgent need for early and effective therapeutic strategies. We isolated a total of 32 phages from water samples and anal swabs from pigs. Of these, three phages that produced large, clear plaques were selected for further study using the following methods: electron microscopy, analysis of the life cycle parameters, genetic analysis, inhibition of bacterial growth, and activity against biofilms. The three Salmonella phages (vB_SenS_CSP01, vB_SenS_PHB06, and vB_SenS_PHB07) were assigned to the family Siphoviridae on the basis of their morphology. All showed polyvalent infectivity, and individual phages or phage cocktails could inhibit the growth of host Salmonella enterica serovar Enteritidis strains or reduce biofilm formation by Salmonella enterica serovar Typhimurium. In summary, these three phages merit further research as biocontrol agents for Salmonella infection.