Harvestman

The harvestman (Hadrobunus grandis) is a common arachnid of eastern North America and Florida, widely recognized by its extremely long legs and small, oval body. Despite its appearance, it is not a spider: it lacks venom glands, silk glands, and the distinct body-segment division of true spiders. One individual was introduced to miniBIOTA in October 2025 and was not observed after two days, with predation by the resident Southern Black Widow considered the most likely cause of disappearance. Population status is Extirpated.

Range and Florida Relevance

Hadrobunus grandis is native to eastern North America, with a range extending from southern Canada through the eastern United States into Florida. In Florida, it is a familiar component of the terrestrial arthropod community in gardens, forest edges, lawns, and humid vegetated areas. It is not a structure-infesting species and poses no threat to humans. Florida's warm, humid climate supports harvestman populations year-round, though activity and abundance may vary seasonally.

Habitat

Harvestmen favor moist, sheltered microhabitats: leaf litter, low vegetation, bark surfaces, and the underside of logs or debris. They are strictly nocturnal in warm climates, spending the day in concealed resting spots and becoming active at night to forage. In a system like miniBIOTA, the Lowland Meadow's leaf litter, soil-surface organic matter, and plant bases, as well as the Lakeshore margin's vegetation and moist substrate edges, represent appropriate habitat types for this species.

Diet

Harvestmen are omnivorous scavengers. They feed on dead invertebrates, carrion, soft plant material, fungi, and occasionally small live prey. Unlike spiders, they cannot inject venom or use webs to capture prey; instead they forage actively across surfaces, using their front legs as sensory organs to detect food. Their chelicerae chew food directly. They are important consumers of small amounts of widely distributed organic matter in terrestrial systems.

Reproduction

Female harvestmen deposit eggs in soil or leaf litter using an elongated ovipositor. Eggs overwinter in temperate regions and hatch in spring, producing nymphs that develop through a series of molts into adults. Hadrobunus grandis is monovoltine in temperate climates, completing one generation per year. Adults typically die after the breeding season; the species persists through egg banks in the substrate.

Tolerance Ranges

Hadrobunus grandis is adapted to the humid, temperate to subtropical conditions of the eastern United States. It is sensitive to desiccation and requires moist refugia; it is most active during humid nights. No miniBIOTA-specific measurements were taken before the individual's disappearance.

In the terrestrial food web, harvestmen function as detritivores, scavengers, and opportunistic omnivores, consuming dead animal and plant material and moving energy through decomposition pathways. They also serve as prey for spiders, centipedes, and other terrestrial predators. Their role in miniBIOTA was purely inferred from published biology; the single introduced individual was present for too brief a period (two days) to produce any observed ecological interaction. Given the Southern Black Widow's presence in overlapping biomes during the same period, the harvestman's most likely role in miniBIOTA was as prey rather than as an active detritivore.

Introduction and History

One harvestman was introduced to the Lowland Meadow and Lakeshore on October 2, 2025. It was last observed on October 4, 2025, two days after introduction. No dedicated observation file was created for the introduction. By October 12, 2025, the individual had not been seen again and was presumed Extirpated, with predation considered the most likely cause. The Southern Black Widow (Latrodectus mactans) was active in the Lowland Meadow during this period and is listed as the probable predator, though no predation event was directly observed. The source and introduction method are unrecorded.