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With about 13,000 known species, ants are the most abundant venomous insects. Their venom consists of polypeptides, enzymes, alkaloids, biogenic amines, formic acid, and hydrocarbons. In this study, we investigated, using in silico techniques, the peptides composing a putative antimicrobial arsenal from the venom gland of the neotropical trap-jaw ant Odontomachus chelifer. Focusing on transcripts from the body and venom gland of this insect, it was possible to determine the gland secretome, which contained about 1022 peptides with putative signal peptides. The majority of these peptides (75.5%) were unknown, not matching any reference database, motivating us to extract functional insights via machine learning-based techniques. With several complementary methodologies, we investigated the existence of antimicrobial peptides (AMPs) in the venom gland of O. chelifer, finding 112 non-redundant candidates. Candidate AMPs were predicted to be more globular and hemolytic than the remaining peptides in the secretome. There is evidence of transcription for 97% of AMP candidates across the same ant genus, with one of them also verified as translated, thus supporting our findings. Most of these potential antimicrobial sequences (94.8%) matched transcripts from the ant's body, indicating their role not solely as venom toxins. [ABSTRACT FROM AUTHOR]

With about 13,000 known species, ants are the most abundant venomous insects. Their venom consists of polypeptides, enzymes, alkaloids, biogenic amines, formic acid, and hydrocarbons. In this study, we investigated, using in silico techniques, the peptides composing a putative antimicrobial arsenal from the venom gland of the neotropical trap-jaw ant Odontomachus chelifer. Focusing on transcripts from the body and venom gland of this insect, it was possible to determine the gland secretome, which contained about 1022 peptides with putative signal peptides. The majority of these peptides (75.5%) were unknown, not matching any reference database, motivating us to extract functional insights via machine learning-based techniques. With several complementary methodologies, we investigated the existence of antimicrobial peptides (AMPs) in the venom gland of O. chelifer, finding 112 non-redundant candidates. Candidate AMPs were predicted to be more globular and hemolytic than the remaining peptides in the secretome. There is evidence of transcription for 97% of AMP candidates across the same ant genus, with one of them also verified as translated, thus supporting our findings. Most of these potential antimicrobial sequences (94.8%) matched transcripts from the ant’s body, indicating their role not solely as venom toxins.

The South America fire ant Solenopsis invicta Buren arrived in Mobile, Alabama by ship sometime before 1945. Since then, S. invicta has spread in North America across the southern US and northeastern Mexico. More recently, it has invaded the West Indies and parts of the Old World. Here, I examine this more recent exotic spread of S. invictabeyond North America, reporting new West Indian records and questioning some Asian records. In 1981, S. invicta was first found in the West Indies, on Puerto Rico. With my new records from Vieques, Aruba, and Jamaica, S. invicta is now known from 28 West Indian islands. In 2001, the first Old World populations of S. invicta were discovered in New Zealand and Australia. Nascent populations of S. invicta in New Zealand have been exterminated and Australia populations have been kept in check through intensive control efforts. Populations of S. invicta in Taiwan and China first found in 2003-2004, however, have spread broadly. Published reports of S. invicta from Malaysia and Singapore were based on misidentifications, presumably of the more widespread Neotropical fire ant, Solenopsis geminata (Fabricius). Reports of S. invicta from India and the Philippines seem questionable and need confirmation. Where S. invicta has invaded, it has displaced S. geminata in open habitats, leaving remnant S. geminata populations, primarily in forested areas. In working to limit the spread and impacts of fire ants, it will be important to differentiate among the species, and recognize their similarities and their differences.

Several species of fire ants, well known for their painful stings, have spread from their native ranges and have become invasive pests, notably Solenopsis geminata, Solenopsis invicta, and Solenopsis richteri. Here, I report the first known exotic spread of another fire ant, Solenopsis nr. saevissima, a South American species now established on the French West Indian island of Guadeloupe. In 2008, I first found this shiny yellow fire ant at Plage de Viard beach on Guadeloupe. Genetic analyses indicated that this species was close to the yellow-brown variant of S. saevissima known only from Western Amazonia, but not an exact match. I returned to Guadeloupe in 2011 and found S. nr. saevissima at Plage de Viard plus five additional sites along a >20 km stretch on the east coast of Basse-Terre, from the Jarry commercial shipping port in the north to Plage Roseau in the south. It seems most likely that S. nr. saevissima arrived in Guadeloupe from South America in a commercial shipment unloaded at the port in Jarry. It is unclear whether this species will develop into a major new problem. Solenopsis nr. saevissima may simply replace another pernicious fire ant, S. geminata, which apparently arrived in Guadeloupe from South America several 100 years ago. [ABSTRACT FROM AUTHOR]