Cobweb Spiders
Theridiidae
Classification
- Phylum: Arthropoda
- Subphylum: Chelicerata
- Class: Arachnida
- Order: Araneae
- Infraorder: Araneomorphae
- Family: Theridiidae
Pronunciation
How to pronounce Theridiidae: /ˌθɛrɪˈdaɪɨdiː/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Images
Summary
Theridiidae, also known as cobweb or comb-footed spiders, are a diverse family of spiders characterized by their unique web-building abilities and morphological features. This family includes over 3,000 species and plays important roles in ecosystems, particularly in pest control.
Physical Characteristics
Theridiidae spiders possess a comb of serrated bristles (setae) on the tarsus of the fourth leg. They are characterized by having first legs that are usually the longest and a round abdomen in most species. They lack thick setae and femoral macrosetae on their legs, which distinguishes them from Linyphiidae spiders.
Identification Tips
To identify Theridiidae, look for the prominent comb-like setae on the tarsus of the fourth leg and note the relative lengths of the legs. The abdomen is generally round rather than elongated.
Habitat
Theridiidae are commonly found in various habitats, including forests, fields, and human dwellings. They often build tangle space webs to trap prey.
Distribution
Globally distributed, with a significant presence in North America.
Diet
Varies across species but includes a range of small insects, often captured in their silk webs.
Life Cycle
Theridiidae exhibit diverse reproductive strategies. Most species lay eggs in silk sacs, which can be guarded by the female. The immature stages may engage in predatory behavior similar to adults.
Reproduction
Females usually exhibit higher levels of parental investment by guarding their egg sacs. Mating behaviors can involve complex interactions, including sexual cannibalism in some species.
Ecosystem Role
Theridiidae spiders play a role in controlling insect populations as predators. They also participate in nutrient cycling within their ecosystems.
Economic Impact
Theridiidae are often encountered in human dwellings and can be beneficial by controlling pest insects, though some members, like widow spiders, are medically significant.
Health Concerns
Some members of the Theridiidae family, specifically the widow spiders, have venom that can be medically significant, though bites are rarely fatal.
Collecting Methods
- Sweep netting
- Hand collecting from webs
- Pitfall traps
Preservation Methods
- Ethanol preservation
- Drying specimens
- Embedding in resin
Evolution
Theridiidae is an ancient family, with fossil evidence dating back to the Cretaceous period. The family shows considerable morphological and ecological diversity, contributing to their widespread distribution.
Similar Taxa
Misconceptions
There is a common misconception that all Theridiidae are highly dangerous or venomous; in reality, many are harmless to humans.
Tags
- spiders
- Theridiidae
- cobweb spiders
- arachnology
- entomology