# Thasus gigas

Thasus gigas, known as giant mesquite bug and xamues, is a species of leaf-footed bug. It is found in Mexico, and less so found in Nicaragua.

## Description

This bug is colorful and large robust insect (6 cm long). Unlike most members of its family (Coreidae), the adults of the giant mesquite bug are colorful with black, orange, and reddish hues. This coloration is considered aposematic, meaning it serves as a warning to predators.
It has a distinctive appearance, with a broad, somewhat flattened body and long, segmented antennae. The nymphs are wingless and feature striking reddish-orange and black coloration, while adults develop fully formed wings and tend to have a darker, more muted appearance. Like other members of Coreidae, Thasus gigas possesses a straw-like proboscis, which it uses to pierce plant tissues and extract sap. One notable characteristic of both nymphs and adults is their ability to excrete a strong-smelling yellow fluid when threatened, serving as a defensive mechanism against predators.

## Range

Thasus gigas thrives in semi-arid regions where mesquite and acacia trees dominate the landscape. This species is particularly abundant in central Mexico, including Querétaro, and is often found in dense populations on host trees such as Brongniartia. It does not appear in the United States, unlike its closely related counterpart, Thasus neocalifornicus, which shares the name Giant Mesquite Bug.
Despite being listed as a common species, observations suggest that its populations are not evenly distributed, with nymphs clustering on select host plants.

## Habitat

Its habitat consists of dry, open landscapes where host trees like Brongniartia, Prosopis, or Acacia provide both food and shelter. The bugs are often found in dense populations on select trees, where eggs are laid, and nymphs develop through multiple stages before reaching adulthood. Since the nymphs lack wings, they remain localized, forming conspicuous clusters on specific trees rather than dispersing widely. The seasonal cycle of these insects aligns with the growth patterns of their host plants, ensuring a steady food source.
Its host plants are primarily mesquites and other Fabaceae members. Their monophagous feeding habits make them dependent on these plants, further linking them to the ecosystems and cultural practices of the regions where they are found. It feeds on the sap, tender leaves, and green pods of various species such as mesquites (Prosopis laevigata, Prosopis juliflora, Prosopis velutina) and huizaches (Vachellia farnesiana), and others such as palo verde (Parkinsonia aculeata), pata de vaca (Bauhinia variegata), palo santo (Platymiscium trifoliolatum), and plumerillos (genus Calliandra).

## Ecology

The species follows a seasonal life cycle, with eggs laid in late August, hatching in October, and progressing through five nymphal stages before winged adults emerge from May to September. Thasus gigas is diurnal, and thus mostly active during the day.
This bug is an abundant and gregarious species. The female lays groups of about forty-five eggs aligned in protected places on the bark and branches of mesquite (Prosopis sp.). The eggs are barrel-shaped, 3 mm long and 1.6 mm in diameter, dark brown in color.
Like other true bugs, the giant mesquite bug undergoes incomplete metamorphosis (hemimetabolism), meaning it does not go through larval and pupal stages. The early stages called "nymphs" are similar in shape to adults but wingless and with different coloration. Before reaching adulthood, the insect goes through five stages, gradually becoming dark brown and growing from 4 mm to 40 mm.

## Indigenous Culture
### Xamues as Food

Thasus gigas plays a significant role in the culture and diet of people in central Mexico, particularly among indigenous Otomí communities. The bugs are traditionally harvested and consumed as a seasonal delicacy, often fried with aromatic herbs and served with salsa, chili peppers, cactus fruits, garlic, and salt. Due to their strong defensive secretion, those collecting them must wear gloves to avoid contact with the stinging yellow fluid. The cultural practice of eating xamues persists, blending traditional knowledge, regional cuisine, and ecological resourcefulness in the semi-arid landscapes where the bug thrives.
T. gigas is traditionally prepared by frying with herbs and wrapping in a tortilla, and modern recipes incorporate them into stir-fried dishes with vegetables, creating a visually striking meal of dark segments mixed with colorful ingredients. The insects are typically harvested during their nymph stages, particularly in the fifth instar before they reach adulthood, as their exoskeletons are likely softer and easier to eat.

### Xamues as Medicine

Thasus gigas (xamues) is traditionally believed to help regulate blood sugar levels, particularly among Otomí communities in the Mezquital Valley of Hidalgo. However scientific research, including a 2014 study, has found no evidence supporting its effectiveness in managing diabetes. Despite this, the belief persists as part of regional food traditions and folk medicine. Xamues is primarily consumed as a protein source, and some preparation methods involve soaking the insects in water and salt to remove a brownish substance, possibly iodine, before incorporating them into traditional dishes.
A survey conducted in Actopan found that 39% of participants had type II diabetes, and among them 53% had consumed xamues as a potential treatment. Notably, 21.5% replaced medical treatment with the insect, and 13% abandoned their prescribed care entirely. While many consume xamues for cultural reasons, with 33% citing tradition as their primary motivation, 68% of surveyed individuals were aware of its use in food and perceived medicinal properties.
While 7% of individuals with type II diabetes reported discontinuing medical treatment in favor of consuming xamues, researchers stress the urgent need for biochemical studies to determine its actual impact on blood glucose levels. Some anecdotal reports suggest adverse effects such as hyperthermia, possibly linked to improper preparation or ingestion of raw insects. Experts emphasize the importance of further research and public health education to prevent the risks associated with unverified treatments, meanawhile xamues remains a culturally significant food. Despite medical advancements, access to healthcare and allopathic medicine remains limited in some communities, leading many to rely on home remedies (including xamues) for diabetes management.

## Etymology

The species is known by various regional names highlighting its deep-rooted presence in local traditions. These names include chinche gigante del mezquite, gusano del mezquite, chinche colorada, cocopaches, chacas, ya xä'u (Otomí language), tantarrias, chagüis, xamues, xagües, and xamuis.