Hippodamia convergens

Guérin-Méneville, 1842

Convergent Lady Beetle, Convergent Ladybug

The convergent is among the most common lady beetles in North America, recognized by the distinctive converging on its . It is a voracious of and other soft-bodied , with both and actively hunting . The exhibits complex traits including facultative reproductive triggered by food scarcity, mass for in western mountain valleys, and long-distance migratory . It is one of the few commercially collected from wild aggregations for distribution, though released often disperse rapidly from release sites.

Hippodamia convergens P1190651b by xpda. Used under a CC BY-SA 4.0 license.Hippodamia convergens P1590869a by xpda. Used under a CC BY-SA 4.0 license.Hippodamia convergens by Jacy Lucier. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Hippodamia convergens: /hɪpoʊˈdeɪmiə kənˈvɜrdʒəns/

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Identification

Distinguished from other by the converging on the that narrow toward the base but do not meet. The 12 black spots on separate it from most other common North , though spot reduction occurs. Hippodamia parenthesis has parenthesis-shaped rather than converging pronotal markings. Hippodamia tredecimpunctata has 13 spots. The Asian lady beetle (Harmonia axyridis) has a black 'M'-shaped marking on the pronotum. The seven-spotted lady beetle (Coccinella septempunctata) has seven spots and lacks converging pronotal lines.

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Habitat

Occupies diverse including grasslands, forests, agricultural fields, gardens, and national parks. In agricultural systems, frequently found in wheat fields and sunflower , where use sunflower for hydration during arid summer months. Shows higher survival and reproductive success in warmer temperatures, with optimal conditions around 25°C and 63% . Temperature ranges from approximately 6.5°C lower limit to 50°C upper limit.

Distribution

to North America with distribution throughout the continent. to South America (Brazil: Minas Gerais, Mato Grosso, Paraná, São Paulo) from California. Present in Caribbean, Middle America, and Oceania regions. In western North America, forms mass in mountain valleys.

Seasonality

Active primarily spring through fall; peak activity during . Females lay during spring and early summer. In western United States, may enter for up to nine months, forming large in mountain valleys during late summer through winter. from sites typically occurs in early spring, with some variation based on temperature and day length cues.

Diet

Both and are active of soft-bodied , with as the primary food resource. Fourth- larvae consume approximately 50 aphids daily; adults consume approximately 20 aphids daily. includes aphids (multiple ), , , and other soft-bodied insects. When aphid prey is scarce, adults feed on , nectar, pollen, and soft parts including petals. First-hatched larvae in a clutch may consume unhatched for initial energy. occurs when food is especially scarce.

Host Associations

  • Acyrthosiphon pisum - ; major ; facultative in this reduce survival
  • Brevicoryne brassicae - ; glucosinolates absorbed by negatively affect development and
  • Myzus persicae - ; supports faster development than B. brassicae
  • Myzaphis rosarum - Rose ; supports faster development than B. brassicae
  • Hamiltonella defensa - indirect Facultative endosymbiont of ; reduces larval survival 2.6×
  • Serratia symbiotica - indirect Facultative endosymbiont of ; reduces larval survival 2.56×
  • Dinocampus coccinellae -
  • Homalotylus terminalis -
  • Tetrapolipus hippodamiae -
  • Metarhizium anisopliae -
  • Beauveria bassiana - ; affects temperature
  • Paecilomyces fumosoroseus -

Life Cycle

with four stages: , , , . Females lay 200–1000 eggs over several months, in upright spindle-shaped batches of 15–30 eggs near . Eggs hatch in approximately 3–5 days. Larvae are dark, somewhat alligator-shaped, and four times over up to one month, growing rapidly. Larvae move between plants by across leaves or through soil when necessary. Pupal stage lasts approximately one week. Adults eclose and mate soon after . If food is abundant, females begin laying within one week; if scarce, may delay up to nine months. Total egg-to-adult development ranges 22–34 days depending on prey and temperature.

Behavior

Active, mobile hunter that travels to locate rather than waiting in ambush. begin searching for prey immediately upon hatching without parental assistance. exhibit pre-reproductive feeding on fats and for approximately one week after , which increases production and promotes ovarian maturation; this also triggers migratory . Forms mass for in western mountain valleys, with adults in diapause known to engage in . Discontinuous food access delays and reduces ; flight distance and fecundity are negatively correlated, indicating energetic trade-offs. Released in programs show strong tendency even when prey remains available.

Ecological Role

Important of pests and other soft-bodied in agricultural and natural . Serves as a model organism for studying movement and in fragmented agricultural landscapes. Facultative in aphid create indirect defense that reduces predator , potentially lowering pressure on aphid through . Contributes to services though effectiveness varies with landscape context and prey availability patterns.

Human Relevance

Widely used for of in greenhouses and field , though effectiveness is limited by rapid of released . One of few still wild-collected from mass in western states for commercial distribution. Not included in University of Florida 2021 guidelines for predatory in control due to dispersal issues. Occasionally bites humans, apparently to obtain salt rather than defensively. sometimes mistaken for pests and killed by gardeners. Subject of ecological research on - dynamics, tri-trophic interactions involving endosymbionts, and movement in agricultural landscapes.

Similar Taxa

Misconceptions

are frequently mistaken for pests due to their alligator-like appearance and killed by gardeners, though they are ferocious of . The 2019 radar-detected 'bloom' in California attributed to convergent was disputed by due to late season timing and cold air temperatures potentially below muscle function thresholds; positive identification was not confirmed.

More Details

Temperature tolerance

Lower lethal limit approximately 6.5°C; upper limit approximately 50°C; optimal reproductive and survival performance at 25.12°C with 63.78%

Commercial collection

Wild collected from mass in mountain valleys of western United States for sale to pest control industry; this practice is rare among

Reproductive plasticity

Females adjust size and trajectories based on body size; large females -load reproductive effort to match , an adaptive strategy constrained by larval food availability

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Sources and further reading