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Convergent Lady Beetle Hippodamia convergens Guérin-Méneville (Insecta: Coleoptera: Coccinellidae)

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The convergent lady beetle, Hippodamia convergens Guérin- Méneville, is among the most common lady beetle species throughout North America and is an important natural enemy of aphids, scales, thrips, and other soft-bodied insects. It will also feed on pollen and nectar from flowers when prey is scarce. This species can be found in habitats ranging from grasslands, forests, agricultural fields, gardens, and natural parks. It is one of the few natural enemies that are currently wild-collected from mass aggregations for distribution to the pest control industry
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EENY592
Convergent Lady Beetle Hippodamia convergens
Guérin-Méneville (Insecta: Coleoptera: Coccinellidae)1
Luis F. Aristizábal and Steven P. Arthurs2
1. This document is EENY592, one of a series of the Entomology and Nematology Department, UF/IFAS Extension. Original publication date June 2014.
Visit the EDIS website at http://edis.ifas.u.edu.
2. Luis Aristizábal, Entomology and Nematology Department; and Steven P. Arthurs, assistant professor, Mid-Florida Research and Education Center;
Entomology and Nematology Department, UF/IFAS Extension, Gainesville, FL 32611.
The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services
only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status,
national origin, political opinions or aliations. For more information on obtaining other UF/IFAS Extension publications, contact your county’s UF/IFAS Extension oce.
U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County
Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.
Introduction
e convergent lady beetle, Hippodamia convergens Guérin-
Méneville, is among the most common lady beetle species
throughout North America and is an important natural
enemy of aphids, scales, thrips, and other so-bodied
insects. It will also feed on pollen and nectar from owers
when prey is scarce. is species can be found in habitats
ranging from grasslands, forests, agricultural elds, gar-
dens, and natural parks. It is one of the few natural enemies
that are currently wild-collected from mass aggregations for
distribution to the pest control industry (Figure 1).
Distribution
Convergent lady beetles are widespread throughout North
America (the United States, western Canada and Mexico)
and Central America, but only recorded from Colombia
in South America (Figure 2). In the United States, the
convergent lady beetle can be found from California to New
Jersey and Hawaii, with smaller populations in the eastern
states. In some areas, the convergent lady beetle, along with
other native species, may be displaced by the invasive Asian
multicolored ladybeetle, Harmonia axyridis (Pallas).
Description
e adult is rounded and elongate-oval, averaging 7.8 mm
(0.3 inch) long for females and 5.8 mm (0.23 inch) long for
males. Adults are easily recognized by their bright red or
Figure 1. Mass of convergent lady beetles in Alamo Peak, Otero Co.,
NM.
Credits: Jerry Oldenettel
Figure 2. Reported geography distribution of the
Hippodamia
convergens
.
Credits: Global Biodiversity Information Facility database
2
Convergent Lady Beetle Hippodamia convergens Guérin-Méneville (Insecta: Coleoptera: Coccinellidae)
orange elytra (hardened forewings) which usually have 12
black spots (6 on each elytron). e prothorax (area behind
the head) is black with a white border and two white,
converging lines, which give rise to the insect’s common
name. Marking on the elytra are variable, with some
individuals less spotted or spotless, but the white lines that
converge behind the head are common to all individuals.
e legs, head, and underside are black. e legs are short
with 3-segmented tarsi, and the antennae are short and
clubbed.
Clusters of yellow eggs are laid by the adult female beetle
in batches of 10-30 eggs on stems or leaves of plants where
abundant insect prey is present. Individual eggs are spindle-
shaped and 1-1.5 mm (≈1/20th inch) long and laid pointing
upwards.
e larvae are black with orange spots on the prothorax
and abdomen and look like small alligators. Larvae develop
through four instars (stages), growing progressively larger
and more spotted with orange and reaching about 7 mm
(1/4 inch) before becoming a pupa. e pupa is hemi-
spherical and orange and black.
Figure 3. Newly emerged adult
Hippodamia convergens showing
typical body markings.
Credits: Luis F. Aristizábal, University of Florida
Figure 4. Eggs of
Hippodamia convergens (1 day old).
Credits: Luis F. Aristizábal, University of Florida
Figure 5. First instar larvae of
Hippodamia convergens.
Credits: Luis F. Aristizábal, University of Florida
Figure 6. Second instar larvae of
Hippodamia convergens.
Credits: Luis F. Aristizábal, University of Florida
Figure 7. Third instar larvae of
Hippodamia convergens.
Credits: Luis F. Aristizábal, University of Florida
3
Convergent Lady Beetle Hippodamia convergens Guérin-Méneville (Insecta: Coleoptera: Coccinellidae)
Seasonal Biology
Convergent lady beetle is a bivoltine species, with two
generations per year (spring and fall) over much of its
range. ere may be additional generations in the South;
the life cycle in Florida has not been reported. During the
summer and winter when temperatures are too high or
low, and during periods when food sources are insucient
for reproduction, adult convergent lady beetles enter into
reproductive diapause. During these periods, adults may
aggregate under tree branches or under rocks.
e abundance of food plays an important role in their
fecundity. Before laying eggs (ovipositing), the female
needs to consume an adequate source of carbohydrates and
proteins. If food is plentiful, the pre-oviposition is about 5
days aer mating (Figure 10); if food is in short supply, the
female may wait several days or weeks before starting to
oviposit. e adults can eat honeydew, nectar, and pollen
when prey is scarce; however, females must consume aphids
or other live prey to reproduce. Each well-fed female may
lay 200 or more eggs during her life. e developmental
period (egg to adult) for convergent lady beetles measured
in our laboratory under conditions of 25°C, 80% relative
humidity and 16 hours daylight is about 21 days (averaging
3.5 days for egg stage, 2.6 days for rst instar, 2.7 days for
second instar, 2.1 days for third instar, 3.8 days fourth instar
and 5.4 days for the pupa).
Predatory Behavior
Convergent lady beetle larvae are active predators and
begin searching for small insects soon aer they hatch from
the egg. In some cases, the unhatched eggs are eaten by the
rst larvae to emerge. Visual, olfactory, and chemical cues,
including pheromones and honeydew secreted by aphids,
may be used to locate prey. Larger larvae are voracious
feeders and may consume between 30 and 50 aphids per
day. When food is scarce, Hippodamia convergens can
become cannibalistic.
is lady beetle is an important natural biological control
agent for aphid pests found on cotton, potato, corn, peach,
melon, cabbage, and other crops. Reported prey include
the Russian wheat aphid, Diuraphis noxia (Nordvilko), the
corn leaf aphid, Rhopalosiphum maidis (Fitch), the bird
cherry oat aphid, Rhopalosiphum padi (L.), the tobacco
aphid, Myzus nicotianae (Blackman), and the pea aphid,
Acyrthosiphon pisum (Harris). Eggs and larvae of other
small insects, such as potato psyllids, Bactericera cockerelli
(Sulc), and asparagus beetles, Crioceris asparagi (L.), are
reported as prey items.
Recently some citrus producers in Florida have released
large numbers of commercially obtained convergent lady
beetles from California against the Asian citrus psyllid
Diaphorina citri (Kuwayama), vector of the causal agent of
Figure 8. Fourth instar larvae of
Hippodamia convergens.
Credits: Luis F. Aristizábal, University of Florida
Figure 9. Pupa of
Hippodamia convergens.
Credits: Luis F. Aristizábal, University of Florida
Figure 10. Ovariole development of
Hippodamia convergens fed
aphids at 25° C.
Credits: Steven Arthurs, University of Florida
4
Convergent Lady Beetle Hippodamia convergens Guérin-Méneville (Insecta: Coleoptera: Coccinellidae)
the devastating Huanglongbing or citrus greening disease
and the citrus aphid, Aphis spiraecola (Patch). However,
there is currently little information on ecacy of this
predator against the psyllid or other pests in citrus groves in
Florida.
Natural Enemies
Generalist predators such as large big-eyed bugs, Geocoris
bullatus (Say), and damsel bugs, Nabis alternatus (Parshley),
are reported as natural enemies of convergent lady beetle
eggs. e braconid wasp Dinocampus (=Perilitus) coccinel-
lae (Schrank) has been found parasitizing convergent lady
beetles (Figure 11). Some microsporidian diseases (primi-
tive fungi) have also been recovered from eld-collected
specimens. e microsporidian Nosema hippodamiae is
thought to cause chronic and sublethal eects, such as
reduced fecundity and survival of adults. Many birds are
predators of ladybeetles as well. However, the red color
with black spots on the elytra may play a role as warning
coloration, and ladybeetles with spots, such as Hippodamia
convergens, tend to be eaten less frequently than unspotted
ones.
Use as a Biological Control Agent
Although convergent lady beetles are generally a solitary
species, they exhibit periodic aggregation behaviors. is
phenomenon is displayed when large numbers of adults
from the fall generation migrate to cooler mountain regions
to overwinter. During the following spring season, these
adults migrate back to agricultural elds, grasslands and
other rural areas in search of aphids and places to lay their
eggs. is aggregation behavior is typical of Hippodamia
convergens but not generally observed in other lady beetle
species except for Harmonia axyridis, which aggregates in
structures.
e most famous large aggregations of this species occur in
the Sierra Nevada Mountains of California. Each year, large
quantities of beetles are collected from these overwintering
sites and put into refrigerated storage before being pack-
aged and distributed to growers and garden outlets. Most
companies package and distribute convergent ladybeetles
in quantities ranging from 1,500 to 72,000 adults for use
against aphids, mites, whiteies, thrips, and mealybugs,
with recommended release rates around 1,500 adults per
500 square feet or 70,000 adults per acre.
e tradition of using this species as a form of natural pest
control has continued, despite reports that eld-collected
beetles may harbor parasites and pathogens that may be
inadvertently released along with the beetles. Moreover,
since most wild-collected beetles overwinter while repro-
ductively immature (ovaries are not yet developed) and
have a natural tendency to disperse away from release sites,
their eectiveness as biological control agents for gardeners
and organic crops production is not guaranteed.
Figure 11.
Hippodamia convergens second instar larvae feeding on
melon aphid.
Credits: Luis F. Aristizábal, University of Florida
Figure 12. Larva of a parasitic wasp (probably Dinocampus
coccinellae) recovered from
Hippodamia convergens.
Credits: Steven Arthurs, University of Florida
Figure 13. Release of
Hippodamia convergens on rose plants.
Credits: Luis F. Aristizábal, University of Florida
5
Convergent Lady Beetle Hippodamia convergens Guérin-Méneville (Insecta: Coleoptera: Coccinellidae)
Selected References
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Darby A, Raymond B, Douglas A. 2003. e olfactory
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Dolenska M, Nedved O, Vesely P, Tesarova M, Fuchs R.
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Eigenbrode SD, White C, Rohde M, Simon CJ. 1998.
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(Coleoptera: Coccinellidae) as a predator of Acyrthosiphon
pisum (Homoptera: Aphididae) on a wax mutant of Pisum
sativum. Environmental Entomology 27: 902-909.
Jamal E, Brown G. 2001. Orientation of Hippodamia
convergens (Coleoptera: Coccinellidae) larvae to volatile
chemicals associated with Myzus nicotianae (Homoptera:
Aphididae). Environmental Entomology 30: 1012-1016.
Joudrey P, Bjørnson S. 2007. Eects of an unidentied
microsporidium on the convergent lady beetle, Hippodamia
convergens Guérin-Méneville (Coleoptera: Coccinellidae),
used for biological control. Journal of Invertebrate Pathology
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Katsarou I, Margaritopoulos J, Tsitsipis J, Perdikis D, Zarpas
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Qureshi JA, Stansly PA. 2011. ree homopteran pests of
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Rodriguez SC, Miller JC. 1995. Life history traits in Hippo-
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The seasonal abundance of 3 species of coccinellids was observed on flue-cured tobacco, Nicotiana tabacum L., during 1997 and 1998 in Tift County, GA. The most abundant coccinellid during both seasons was the convergent lady beetle, Hippodamia convergens Guérin-Méneville, which was present from mid-May, when tobacco aphids, Myzus nicotianae Blackman, colonized the crop, until late July when sampling ended. The sevenspotted lady beetle, Coccinella septempunctata L., and the multicolored Asian lady beetle, Harmonia axyridis (Pallas), were also observed. C. septempunctata was most abundant early in the season and maintained low population levels during June and July. Conversely, H. axyridis was absent in tobacco until late May and remained abundant until sampling was discontinued. Populations of H. convergens, H. axyridis, and C. septempunctata were linearly related to tobacco aphid populations during 1998. In functional response experiments, 4th-instar larvae and adult H. convergens exhibited a type II functional response to aphid density. Fourth-instar larvae had a higher search rate and a longer handling time than adult H. convergens. Two other coccinellid species were observed at low population densities on flue-cured tobacco, Coleomegilla maculata (Mulsant) and Cycloneda munda (Say). Collectively, coccinellids may be important biological control agents of tobacco aphids on Georgia flue-cured tobacco.
Article
Convergent lady beetles, Hippodamia convergens Guérin-Méneville, are a popular choice for aphid control in North America. An unidentified microsporidium was found in H. convergens adults that were purchased from a commercial insectary in 2004. This study examined egg cannibalism and egg predation as a means of horizontal transmission of the unidentified microsporidium among H. convergens larvae and three coccinellid species found in Nova Scotia: Coccinella septempunctata (seven-spotted lady beetle), C. trifasciata perplexa (three-banded lady beetle), and Harmonia axyridis (multicolored Asian lady beetle). The microsporidium was transmitted with 100% efficiency when first instars fed on microsporidia-infected eggs. Mean spore count data from smear preparations of infected beetles suggest that the infection was as heavy in C. trifasciata perplexa (a native coccinellid) (11.2 ± 0.96 spores/100 μm2) as it was in H. convergens (the natural host) (12.8 ± 1.16) but lighter in the introduced species C. septempunctata (7.5 ± 0.65) and H. axyridis (0.8 ± 0.11). For all of the beetle species examined, larval development was significantly longer for microsporidia-infected individuals than for their uninfected cohorts. The microsporidium had no effect on larval mortality. Based on the results of this study, field-collected H. convergens should be examined for microsporidia and uninfected individuals should be used to rear individuals for release in biological control programs. However, this is unlikely to happen because H. convergens are relatively easy and inexpensive to collect from their overwintering sites for redistribution.