Predicting the Global Distribution of Solenopsis geminata (Hymenoptera: Formicidae) under Climate Change Using the MaxEnt Model

The tropical fire ant Solenopsis geminata (Hymenoptera: Formicidae) is a serious invasive species that causes a decline in agricultural production, damages infrastructure, and harms human health. This study was aimed to develop a model using the maximum entropy (MaxEnt) algorithm to predict the current and future distribution of S. geminata on a global scale for effective monitoring and management. In total, 669 occurrence sites of S. geminata and six bioclimatic variables of current and future climate change scenarios for 2050 and 2100 were used for the modeling. The annual mean temperature, annual precipitation, and precipitation in the driest quarter were the key influential factors for determining the distribution of S. geminata. Although the potential global distribution area of S. geminata is predicted to decrease slightly under global warming, the distribution of favorable habitats is predicted to expand to high latitudes under climate scenarios. In addition, some countries in America and East Asia, such as Brazil, China, South Korea, the USA, and Uruguay, are predicted to be threatened by S. geminata invasion under future climate change. These findings can facilitate the proactive management of S. geminata through monitoring, surveillance, and quarantine measures.

Carriers and cutters: size-dependent caste polyethism in the tropical fire ant (Solenopsis geminata)

Body size is an important life-history trait in eusocial insects which plays a key role in colony fitness. The division of labour, represented by caste polyethism, correlates with divergent morphological traits. Size polymorphism has been noted in the tropical fire ant, Solenopsis geminata; however, little is known regarding the differences in the size distributions of workers performing foraging tasks. In the present study, task partitioning was observed in the foraging activities of S. geminata. Two subgroups among foraging workers of S. geminata were discovered using the Gaussian mixture model: a large worker group (head width ≥ 0.924 mm) and a small worker group (head width < 0.924 mm). The foraging worker population comprised two distinct groups – 25.64% were large workers and 74.36% were small workers. Larger workers delivered heavier seeds faster than smaller workers, but this difference became less apparent when lighter seeds were being carried. When large prey such as crickets was encountered during foraging, S. geminata partitioned their tasks into cutting and transportation. The large workers were observed to cut cricket prey into fragments with their longer mandibles, and the small workers then transported these fragments back to the nest. These results present evidence of task partitioning among tropical fire ants, with different tasks being performed by ants of different castes.

Ant Diversity (Hymenoptera: Formicidae: Myrmicinae) in Three Housing Types in Bandar Lampung

Bandar Lampung City has a population of 1.051.500 people with a density of 3.308,4 people/km2 in 2018. The population is densely accompanied by residential developments, one of which is housing. Housing in the city of Bandar Lampung amounted to 220 housing estates in 2018 consisting of types 21, 36, 45.54, and 70. Rapidly increasing development certainly affected the surrounding ecosystem. The ant is one indicator of change in the environment. Therefore it is important to research the identification of Myrmicinae ants in three types of housing in Bandar Lampung City. The research was conducted in November - October 2018. This type of research is quantitative with survey methods. The housing of each type is selected by random sampling then ant samples are taken using the standardized transect method. Two transects were installed in the yard of the house and a roadside transect. The ants obtained were identified using photographs, images and the key of determination. The results showed that there were 5 species of Myrmicinae from 3 genera namely Solenopsis geminata, Solenopsis invicta, Solenopsis molest, Tetramorium sp., and Monomorium sp. The most dominant subfamily Formicidae habitats are in the house and terrace house.

Nuevos registros de hormigas (Hymenoptera: Formicidae) en la Isla María Cleofas, Golfo de California, México

La mirmecofauna de la Isla María Cleofas, una de las cuatro áreas insulares de la Reserva de la Biosfera del archipiélago de las Islas Marías en el Golfo de California, México, es poco conocida. En este trabajo se registran por primera vez para la isla a Camponotus atriceps, C. rectangularis, Leptogenys ixta, Pseudomyrmex elongatus y Solenopsis geminata. Asimismo, la documentación fotográfica previa de Atta mexicana en la localidad, fue confirmada por la revisión de especímenes.