INTERESTING INSECTS

By N A Martin (2015 revised 2016)

Eleven-spotted ladybird

Coccinella novaezealandiae Colenso, 1888

This adventive ladybird comes from the northern hemisphere. It is present in Europe, Asia and North America. It is now widespread in New Zealand, where it occurs in grasslands, vegetable crops, field crops, cereals, and other habitats with low-growing vegetation where it feeds on a variety of insects.

Conservation status: Eleven-spotted ladybird is widespread and not threatened. It is a useful biological control agent in many commercial and domestic crops.

The adults are mainly coloured red and black. The elytra (wing covers) are red with the characteristic 11 black spots. The size and arrangement of spots may vary and the small front spots may become very small, almost invisible. The prothorax (first segment with legs) and the head are black with white areas; the prothorax has a pair of white areas at the front and side. Under the elytra is a pair of wings used for flying. Like most insects, this ladybird has three pairs of legs that are coloured black. The small head has a pair of compound eyes and two short antennae. Female ladybirds lay small groups of yellow eggs on leaves, usually near infestations of prey. A long, dark larva hatches from each egg. The larva is dark grey with rows of black tubercles on the dorsal (upper) side of the abdominal and thoracic segments. The three pairs of legs are used for walking. They don’t appear to be used for holding prey. As the larva grows, it moults (changes skin). There are four larval instars (stages). The older instars have pale spots on certain abdominal segments, the arrangement of which is characteristic of the species. When the fourth larval instar is fully grown, it attaches itself to a sheltered place on a plant and moults into a pupa. The pupa remains attached to the plant by its hind end, which is usually surrounded by the moulted larval skin. If disturbed, the pupa can wag up and down. Adults hatch from pupae and mate. The length of time of each life stage depends on temperature, being shorter at higher temperatures.

Annual cycle-overwintering

Adult eleven-spotted ladybirds overwinter, often sheltering in large groups. In Canterbury, they hibernate from April to September on Thuja orientalis L. (white cedar), kowhai, (Sophora tetraptera), among needles on lateral shoots of Pinus radiata, under loose bark, and in cracks in old wooden fence posts. The same overwintering sites may be used every year.

Annual cycle-breeding

In spring (August onwards), overwintering females feed and lay eggs. Larvae may be present from late September onwards. There are at least two generations per year; the first coincides with the spring flush of plant growth and high aphid populations.

Feeding

The adult and larval ladybirds eat aphids and other insects. The larvae may also eat one another. The jaws are the primarily structures used for holding and chewing the prey. Legs do not appear to be used for holding food.

Yellow eggs of eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae). Creator: Plant & Food Research Photographer. © Plant & Food Research. [Image: 15A1]

A young larva of an eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae) feeding on aphids. Creator: Tim Holmes. © Plant & Food Research. [Image: 159N]

A large larva of an eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae) feeding on a caterpillar. Creator: Tim Holmes. © Plant & Food Research. [Image: 159P]

Side view of a large larva of an eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159U]

Underside of a large larva of an eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159W]

A pupa of an eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae). The skin of the larva is around the rear (anal) end, which holds the pupa onto the surface. Note the dark wing buds. Creator: Tim Holmes. © Plant & Food Research. [Image: 159Z]

Dorsal view of a pupa of an eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae)A pupa of an eleven spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae). The skin of the larva is around the rear (anal) end, which holds the pupa onto the surface. Note the dark wing buds. Creator: Tim Holmes. © Plant & Food Research. [Image: 15A0]

Adult eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae) feeding on an aphid. Creator: DSIR Photographers. © Plant & Food Research. [Image: 15A5]

Adult eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159S]

Underside of an adult eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159T]

Side view of an adult eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae) with only 9 spots and yellow halos around the spots. Creator: Tim Holmes. © Plant & Food Research. [Image: 15A2]

Side view of an adult eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 15A4]

Adult eleven-spotted ladybirds are easily recognised; they have red elytra (wing covers) with 11 black spots. The size and position of the black spots can vary. For example the two posterior spots may join together and the small front spot may become very small and not be clearly visible, giving the appearance of the ladybird only having nine spots. One recently found adult had a yellow halo around each black spot.

Older larvae have four distinct pale markings on the upper side of the abdominal segments. There is also a pale spot on the outer edges of abdominal segments 1 and 4.

Adult eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae) on a lettuce leaf. Creator: Plant & Food Research Photographer. © Plant & Food Research. [Image: 159M]

A fully grown larva of eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159Q]

Side view of a large larva of an eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159U]

Larva of eleven-spotted ladybird, Coccinella undecimpunctata, (Coleoptera: Coccinellidae), (left) and two other ladybirds. Creator: DB Read. © Drawings published in New Zealand Entomologist 1965, volume 3 (4): 14-17, Figures 1-3. [Image: 15A6]

Side view of an adult eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae) with only 9 spots and yellow halos around the spots. Creator: Tim Holmes. © Plant & Food Research. [Image: 15A2]

An adult eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae) with only 9 spots and yellow halos around the spots. Creator: Tim Holmes. © Plant & Food Research. [Image: 15A3]

Predators

In New Zealand, adult and larval eleven-spotted ladybirds are eaten by several bird species. They are a prominent part of the diet of older sparrow nestlings. They may also be eaten by predatory insects including their own species.

Pathogens

The insect pathogenic fungus, Beauvaria bassiana (Balsamo) Vuillemin, may kill 56-90% of overwintering adult ladybirds in wet winters.

Parasitoids

Adult ladybirds may be parasitized by Dinocampus coccinellae (Shrank 1802) (Hymenoptera: Braconidae). This wasp may cause heavy parasitism in late winter and up to 85% parasitism from mid-summer onwards. The parasitoid attacks other species of ladybird. The adult female parasitoid lays an egg in the adult ladybird. The parasitoid larva develops in the live ladybird. When it is fully grown it exit on the underside of the ladybird and spins a cocoon with the adult ladybird attached on top. The parasitoid larva pupates in the cocoon. The adult parasitoid, after hatching form the pupa and its skin hardening, chews its way out of the cocoon. The still live, but very weak adult ladybird is still stuck on top of the cocoon.

Adult eleven-spotted ladybird, Coccinella undecimpunctata, (Coleoptera: Coccinellidae), on a cocoon of the parasitoid Dinocampus coccinellae (Shrank 1802) (Hymenoptera: Braconidae), note the opened cap through which the adult parasitoid emerged. Creator: Tim Holmes. © Plant & Food Research. [Image: 159G]

Adult eleven-spotted ladybird, Coccinella undecimpunctata, (Coleoptera: Coccinellidae), on a cocoon of the parasitoid Dinocampus coccinellae (Shrank 1802) (Hymenoptera: Braconidae), note the opened cap through which the adult parasitoid emerged. Creator: Tim Holmes. © Plant & Food Research. [Image: 159H]

Top view of adult ladybird parasitoid Dinocampus coccinellae (Shrank 1802) (Hymenoptera: Braconidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159J]

Top view of adult ladybird parasitoid Dinocampus coccinellae (Shrank 1802) (Hymenoptera: Braconidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159I]

Underside of adult ladybird parasitoid Dinocampus coccinellae (Shrank 1802) (Hymenoptera: Braconidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159K]

Underside of adult ladybird parasitoid Dinocampus coccinellae (Shrank 1802) (Hymenoptera: Braconidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159L]

This ladybird has been recorded feeding on several aphid species that live on vegetable crops, cereals, and grassland plants. Although usually regarded as an aphid predator, it has also been recorded feeding on caterpillars, butterfly eggs, psyllids, and a species of Collembola (springtails), lucerne flea (Sminthurus viridis L.). Larvae are also cannibalistic, usually feeding on other larvae when prey is scarce. It is probable that the species has a wide prey range.

A small larva of an eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae) feeding on a green peach aphid, Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159X]

A small larva of an eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae) feeding on a green peach aphid, Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159Y]

A large larva of an eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae) feeding on a tomato/potato psyllid, Bactericera cockerelli (Sulc, 1909) (Hemiptera: Triozidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159R]

A large larva of an eleven-spotted ladybird, Coccinella undecimpunctata (Coleoptera: Coccinellidae) feeding on a caterpillar of diamondback moth, Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 159V]

Arrival in New Zealand

It was long believed that eleven-spotted ladybird was deliberately released in New Zealand. One early New Zealand Entomologist, Dr David Miller, reported the supposed 1874 introduction (release) but also commented that it could have arrived and become established as early as 1837. There are also reports that this ladybird was obtained from the Entomological Society of London and were released into New Zealand in 1874 by the Canterbury Acclimatization Society. This would make it the earliest biological control agent to be deliberately released into New Zealand for the control of insect pests. However, recent research by Dr Ross Galbraith and Dr Peter Cameron found no evidence for the collection of the eleven-spotted ladybird in England and its deliberate release in New Zealand, and documented the process of cumulative misreporting that created the record. This record should therefore be removed from databases or summaries of the history of biological control.

Warning colouration

The bright colour of some ladybirds is believed to be a warning to potential predators such as birds. These brightly coloured ladybirds contain various alkaloids that may make the beetles taste unpleasant; eleven spotted ladybird contains the chemical coccinelline. This chemical can deter feeding by ants and birds. Ladybirds with warning colouration also exhibit ‘reflex bleeding’, emitting blood containing the alkaloids.

Aggregation

This ladybird may also emit another chemical, an aggregation pheromone.

Diverse habits of 'ladybirds'

Not all ladybirds eat insects; some feed on mites. Other species eat plant leaves and are pests in some tropical countries, whereas others feed on fungi. One of these, Illeis galbula Mulsant (1850), is common in New Zealand and feeds on powdery mildew fungi. It is common on pumpkins and other cucurbits, plants that are commonly infected by powdery mildews.

Biological control of pests

Biological control of aphids and other herbivorous pests can reduce the impact of the pests and the need to use insecticides. Eleven spotted ladybird are important predators in grasslands, various vegetable crops, and in the home garden. If pesticides are needed to control other pests, it is advisable to use chemicals that will have minimal harmful effects on the ladybirds or to use them at a time when the ladybirds are not present.

Colenso W. 1888. A description of a new species of Coccinella found in New Zealand. Transactions and proceedings of the New Zealand Institute, 20: 40-42.

Galbreath RA, Cameron PJ. 2015. The introduction of the eleven-spotted ladybird Coccinella undecimpunctata L. (Coleoptera: Coccinellidae) to New Zealand in 1874: a spurious

record created by cumulative misreporting. New Zealand Entomologist 38: 7-9.

King AG, Meinwald J 1996. Review of the defensive chemistry of coccinellids. Chemistry Review 96: 1105-1122.

Plant-SyNZ: Invertebrate herbivore-host plant association database. plant-synz.landcareresearch.co.nz/.

Thomas WP 1989. Aphididae, aphids (Homoptera). In: Cameron PJ, Hill RL, Bain J, Thomas WP eds. A Review of Biological Control of Invertebrate Pests and Weeds in New Zealand 1874 to 1987. Technical Communication No. 10. Wallingford, UK, CAB International Institute of Biological Control. Pp. 55-66.

Valentine EW 1967. A list of the hosts of entomophagous insects of New Zealand. New Zealand Journal of Science 10(4): 1100-1209.

Thanks to Frances MacDonald for providing insects and arranging for them to be photographed, and Graham Walker and Peter Workman for information about the ladybird and its prey.

Thanks to Peter Cameron for information about the origins of the ladybird in New Zealand.

The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research) for permission to use photographs.

1 November 2018. NA Martin. Changed symbol used for apostrophes.

21 December 2016. NA Martin. Additional Information: Arrival in New Zealand rewritten.