Mastophora leucabulba
(Gertsch, 1955)
Mastophora leucabulba is a bolas spider in the orb-weaver Araneidae. females hunt using a single sticky silk droplet suspended from a dragline rather than building an orb web. Males and females lack this specialized hunting method and capture prey directly with their legs. The occurs from the United States to Honduras.
Pronunciation
How to pronounce Mastophora leucabulba: /ˌmæstəˈfɔrə ˌloʊkəˈbʌlbə/
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Identification
The Mastophora is distinguished from other Araneidae by the highly modified hunting of females. Within the genus, M. leucabulba can be identified by its geographic range (United States to Honduras) and specific epithet characteristics. However, -level identification of Mastophora is challenging and typically requires examination of genitalia or sac . The black and white mottled egg sacs are a useful field indicator for the genus.
Habitat
Specific preferences for M. leucabulba are not documented. Based on -level information, Mastophora are and hide during daylight hours, resting on vegetation where their bird-dropping mimicry provides camouflage. They occupy wooded or shrubby environments where their prey occurs.
Distribution
United States to Honduras. Records indicate presence in Middle America and North America, with the range spanning from the southern United States through Central America to Honduras.
Diet
females are highly specialized of male noctuid . They achieve this by emitting the of female moths to lure males within striking distance of the bolas. Males and females feed on smaller prey, including male phorid flies (humpbacked flies), captured directly with their legs.
Host Associations
Life Cycle
Males emerge from sacs as instars, requiring only one to reach maturity. This abbreviated development results in markedly smaller males compared to females. Females construct black and white mottled egg sacs that are attached to vegetation. Detailed timing for this is not documented.
Behavior
females are sit-and-wait that remain stationary at night, emitting and sensing air vibrations from approaching moth wings. Upon detecting prey, they swing the sticky bolas in a pendulum-like motion to capture the moth, then reel in the prey. This represents one of the most specialized hunting known in spiders. Females are inactive and hidden during daylight hours.
Ecological Role
As a specialized of male , M. leucabulba exerts sex-biased pressure on noctuid moth . The -based hunting strategy represents a rare example of aggressive chemical mimicry in arthropods. Juveniles and males likely serve as predators of small flies in the .
Human Relevance
No direct human relevance documented. The is rare in collections and not commonly encountered due to its habits and cryptic daytime appearance. sacs may be mistaken for plant structures or lepidopteran cocoons by observers.
Similar Taxa
- Other Mastophora speciesAll 15 Mastophora in the United States share the bolas hunting and bird-dropping mimicry. M. cornigera is the only other species recorded from California; other species require geographic or morphological distinction.
- Typical Araneidae orb-weaversUnlike conventional orb-weavers, Mastophora do not construct capture webs. females can be distinguished by their specialized hunting posture with a single silk line and droplet.
More Details
Taxonomic history
The Mastophora was recently re-revised, with ongoing taxonomic work clarifying boundaries. Mastophora species are among the least commonly collected araneids due to their cryptic habits.
Hunting mechanism
The bolas hunting method represents an evolutionary departure from the ancestral orb-weaving of Araneidae. The single sticky droplet is produced from specialized silk glands, and the spider detects prey approach through air-borne vibrations rather than web-borne signals.