Most described Mesozoic ants belong to stem groups that existed only during the Cretaceous period. Previously, the earliest known crown ants were dated to the Turonian (Late Cretaceous, ca. 94-90 million years ago (Ma)) deposits found in the USA, Kazakhstan, and Botswana. However, the recent discovery of an alate male ant in Kachin amber from the earliest Cenomanian (ca. 99 Ma), representing a new genus and species, Antiquiformica alata, revises the narrative on ant diversification. Antiquiformica can be distinctly differentiated from all known male stem ants by its geniculate antennae with elongated scape, extending far beyond the occipital margin of the head and half the length of the funiculus, as well as its partly reduced forewing venation. Furthermore, the combination of a one-segmented waist with a well-developed node, elongated scape extending beyond the occipital margin, and reduced forewing venation, particularly the completely reduced m-cu and rs-m crossveins and absence of rm and mcu closed cells, firmly places the fossil within the extant subfamily Formicinae. Fourier transform infrared spectroscopy (FTIR) confirmed that the amber containing Antiquiformica alata originated from the Kachin mines in Myanmar. This discovery significantly revises our understanding of the early evolution of Formicinae. The presence of Antiquiformica in Cenomanian amber indicates that the subfamily Formicinae emerged at least by the start of the Late Cretaceous, with crown ants likely originating earlier during the earliest Cretaceous or possibly the Late Jurassic, although paleontological evidence is lacking to support the latter hypothesis.
大多数被描述的中生代蚂蚁属于仅生存在白垩纪的基干类群。目前已知最古老的冠群蚂蚁发现于美国、哈萨克斯坦和博茨瓦纳的土仑阶沉积中（晚白垩纪，约94–90 Ma）。然而，在克钦琥珀中发现的一个森诺曼阶早期的有翅雄蚁新种（约99 Ma）——翼古老蚁（ Antiquiformica alata）改变了对蚂蚁类群分化的认识。古老蚁属（ Antiquiformica）与所有已知的雄性蚂蚁明显不同：触角呈膝状；柄节较长，延伸远超过后头边缘，长度约为鞭小节的一半；前翅翅脉部分减少。此外，古老蚁属（ Antiquiformica）具有一个发育良好的腹结节、延伸超过后头边缘的细长柄节、简化的前翅翅脉，尤其是前翅横脉m-cu和rs-m完全消失、翅室rm和mcu不闭合，这些特征都表明翼古老蚁属于现存的蚁亚科。傅里叶红外光谱（FTIR）结果表明这件琥珀来自缅甸克钦矿区。新化石的发现极大地改变了我们对蚁亚科早期演化的认识。在克钦琥珀（森诺曼阶）中发现的古老蚁属（ Antiquiformica）证实蚁亚科至少在晚白垩的早期就已经出现，而冠群蚂蚁出现时间肯定更早。冠群蚂蚁可能起源于白垩纪早期甚至侏罗纪晚期，尽管这一假设还未得到古生物学证据的支持。.

The clonal raider ant, Ooceraeabiroi, is a queenless species that reproduces asexually, and these traits make it an attractive model system for laboratory research. However, it is unclear where on the ant phylogeny these traits evolved, partly because few closely related species have been described and studied. Here, we describe a new raider ant species, Ooceraeahainingensis sp. nov., from Zhejiang, China. This species is closely related to O.biroi but can be distinguished by the following features: 1) workers of O.hainingensis sp. nov. have an obvious promesonotal suture and a metanotal groove, whereas these characters are ambiguous in O.biroi; and 2) the subpetiolar process of O.hainingensis is prominent and anteroventrally directed like a thumb with sublinear posteroventral margin, while in O.biroi, it is anteroventrally directed but slightly backward-bent. Molecular phylogenetic analyses confirm that O.hainingensis is genetically distinct from O.biroi. Importantly, unlike O.biroi, O.hainingensis has a queen caste with wings and well-developed eyes. This suggests that the loss of the queen caste and transition to asexual reproduction by workers is specific to O.biroi and occurred after that species diverged from closely related congeneric species.

Ground-dwelling invertebrates are vital for soil biodiversity and function maintenance. Contemporary biodiversity assessment necessitates novel and automatic monitoring methods because of the threat of sharp reductions in soil biodiversity in farmlands worldwide. Using infrared camera traps (ICTs) is an effective method for assessing richness and abundance of ground-dwelling invertebrates. However, the influence that the shooting area of ICTs has on the diversity of ground-dwelling invertebrates has not been strongly considered during survey design. In this study, data from six ICTs with two shooting areas (A1, 38.48 cm2; A2, 400 cm2) were used to investigate ground-dwelling invertebrates in a farm in a city on the Eastern Coast of China from 20: 00 on July 31 to 00:00 on September 29, 2022. Over the course of 59 days and 1420 h, invertebrates within 9 taxa, 2447 individuals, and 112,909 ind./m2 were observed from 222,912 images. Our results show that ICTs with relatively large shooting areas recorded relatively high taxonomic richness and abundance of total ground-dwelling invertebrates, relatively high abundance of the dominant taxon, and relatively high daily and hourly abundance of most taxa. The shooting areas of ICTs significantly affected the recorded taxonomic richness and abundance of ground-dwelling invertebrates throughout the experimental period and at fine temporal resolutions. Overall, these results suggest that the shooting areas of ICTs should be considered when designing experiments, and ICTs with relatively large shooting areas are more favorable for monitoring the diversity of ground-dwelling invertebrates. This study further provides an automatic tool and high-quality data for biodiversity monitoring and protection in farmlands.

The eusocial pest, red imported fire ant (Solenopsis invicta), is a highly invasive species that poses significant threats to public safety, agriculture, and the ecological environment. Cycloxaprid, a newly identified effective, slow-acting, and non-repellent insecticide against S. invicta, allows contaminated individuals to transfer the insecticide among nestmates through body contact. However, the molecular-level changes occurring in S. invicta post cycloxaprid exposure and any molecular alterations contributing to the slow demise or decreased sensitivity remain unclear. In this study, transcriptomic and metabolomic techniques were used to investigate the molecular mechanisms of S. invicta exposed to cycloxaprid. Differential analysis results revealed 275, 323, and 536 differentially expressed genes at 12, 24, and 48 h, respectively. Genes involved in lipid and energy metabolism, DNA integration, and hormone synthesis were largely upregulated at 12 h, suggesting S. invicta might actively resist cycloxaprid impacts, and predominantly downregulated at 48 h, indicating further functional impairment and impending death. Also, we observed an imbalance in olfactory perception pathways at 12 h, which may indicate a disruption in the olfactory system of S. invicta. Metabolomic results showed that the regulation of most differential metabolites (DMs) was consistent with the expression changes of their related DEGs at different time points. Our study provides insights into the mechanism underlying slow-acting and non-repellent properties of cycloxaprid against S. invicta.

Plant diversity can increase productivity. One mechanism behind this biodiversity effect is facilitation, which is when one species increases the performance of another species. Plants with extrafloral nectaries (EFNs) establish defense mutualisms with ants. However, whether EFN plants facilitate defense of neighboring non-EFN plants is unknown. Synthesizing data on ants, herbivores, leaf damage, and defense traits from a forest biodiversity experiment, we show that trees growing adjacent to EFN trees had higher ant biomass and species richness and lower caterpillar biomass than conspecific controls without EFN-bearing neighbors. Concurrently, the composition of defense traits in non-EFN trees changed. Thus, when non-EFN trees benefit from lower herbivore loads as a result of ants spilling over from EFN tree neighbors, this may allow relatively reduced resource allocation to defense in the former, potentially explaining the higher growth of those trees. Via this mutualist-mediated facilitation, promoting EFN trees in tropical reforestation could foster carbon capture and multiple other ecosystem functions.

Island systems are known to harbor disproportionate amounts of geographically restricted biodiversity and to experience high rates of species loss, and they ultimately represent critical systems with significant conservation values. However, knowledge of the biodiversity value of insular systems remains highly fragmented and incomplete for many groups of organisms, especially insects. This gap limits our understanding of their global significance for biodiversity and inhibits prioritization for future exploration and conservation efforts. Here, we developed a new database to present current knowledge on ants on 2678 islands globally, based on nominal species, and provide information on their native or exotic status. In total, this database contains 7010 ant species (44.6% of the known global ant fauna) that have been recorded on islands globally from 449,232 records. In addition, this database identifies 108 large islands (area > 200 km2 ) that have received no ant sampling efforts globally. This new data set provides the most comprehensive understanding of ant diversity and composition on islands globally, opening up new opportunities to address questions on a multitude of research questions and fields related to biogeography, ecology, and evolution. This data set also provides a roadmap for future exploration and conservation actions in connection with ants on islands as well as overall ant diversity, with updates available as new records and taxonomic updates are published. There are no copyright restrictions on this database and users should cite this data paper in publications when using the data.

Ants (Hymenoptera: Formicidae) are among the largest and most widespread families of terrestrial insects and are valuable to medical and ecological investigations. The mitochondrial genome has been widely used as a reliable genetic marker for species identification and phylogenetic analyses. To further understand the mitogenome-level characteristics of the congeneric Formicidae species, the complete mitogenome of Formica sinae (Hymenoptera: Formicidae) was sequenced, annotated, and compared with other 48 Formicidae species. The results showed that gene composition, content, and codon usage were conserved. The complete mitochondrial genome of F. sinae was 17,432 bp, including 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs), and one control region located between rrnS and trnM, which was 1,256 bp long, the longest of all sequenced species. Gene rearrangement was not detected in Formica species (Hymenoptera: Formicidae). All PCGs of F. sinae were initiated with ATN codons and terminated with the TAA codon. The overall nucleotide composition of F. sinae was AT-biased (83.51%), being 80.58% in PCGs, 86.68% in tRNAs, 87.10% in rRNAs, and 88.70% in the control region. Phylogenetic analyses indicated that each subfamily formed a strongly monophyletic group. Furthermore, F. sinae clustered with Formica fusca (Hymenoptera: Formicidae) and Formica selysi (Hymenoptera: Formicidae). This work enhances the genetic data of Formicidae and contributes to our understanding of their phylogenic relationship, evolution, and utilization.

Knowledge on the distribution and abundance of organisms is fundamental to understanding their roles within ecosystems and their ecological importance for other taxa. Such knowledge is currently lacking for insects, which have long been regarded as the \"little things that run the world\". Even for ubiquitous insects, such as ants, which are of tremendous ecological significance, there is currently neither a reliable estimate of their total number on Earth nor of their abundance in particular biomes or habitats. We compile data on ground-dwelling and arboreal ants to obtain an empirical estimate of global ant abundance. Our analysis is based on 489 studies, spanning all continents, major biomes, and habitats. We conservatively estimate total abundance of ground-dwelling ants at over 3 × 1015 and estimate the number of all ants on Earth to be almost 20 × 1015 individuals. The latter corresponds to a biomass of ∼12 megatons of dry carbon. This exceeds the combined biomass of wild birds and mammals and is equivalent to ∼20% of human biomass. Abundances of ground-dwelling ants are strongly concentrated in tropical and subtropical regions but vary substantially across habitats. The density of leaf-litter ants is highest in forests, while the numbers of actively ground-foraging ants are highest in arid regions. This study highlights the central role ants play in terrestrial ecosystems but also major ecological and geographic gaps in our current knowledge. Our results provide a crucial baseline for exploring environmental drivers of ant-abundance patterns and for tracking the responses of insects to environmental change.

Messor structor (Latreille, 1798) is a keystone ant species in the genus Messor (Formicidae: Myrmicinae). Here, we reported the complete mitochondrial genome of M. structor. The circular mitogenome of M. structor is 17628 bp including 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, and a control region. The base composition was AT-biased (84.07%). Phylogenetic analysis suggests that it is closely related to Aphaenogaster famelica. The mitochondrial genome of M. structor will be a good source for understanding molecular evolutionary studies of this species and related ant species.

Camponotus japonicus Mayr, 1866 is a widespread and open-field formicine ant species in east Asia. In this study, we sequenced and analyzed the complete mitochondrial genome (mitogenome) of C. japonicus. This mitogenome was 16,422 bp long and encoded 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs) and two ribosomal RNA unit genes (rRNAs). Gene order was conserved and identical to most other previously sequenced Formicidae. All PCGs of C. japonicus have the conventional start codon for invertebrate mitochondrial PCGs (five ATT, four ATA and four ATG). All PCGs terminated with the stop codon TAA. The whole mitogenome exhibited heavy AT nucleotide bias (77.8%). Phylogenetic analysis positioned C. japonicus in a well-supported clade with C. atrox and C. concavus, and C. japonicus was more closely related to C. atrox than to C. concavus. Within Formicinae, the topology (Colobopsis + (Polyrhachis + Camponotus) + (Formica + (Nylanderia + Lasius) + (Anoplolepis + Acropyga))) was recovered.