INTERESTING INSECTS

By N A Martin (2016 revised 2018)

Yellow haired ladybird

Scymnus flavihirtus Broun, 1880

Adoxellus concinnus Weise, 1895

This endemic ladybird is found in the North and South) Islands of New Zealand. Adults and larvae feed on small insects.

Conservation status: This native ladybird is widespread, but not commonly caught.

The adults are small, about 3.5 millimetres long. The head, prothorax (first part of the middle body) and elytra (wing covers) are covered in short yellow-tan coloured setae (hairs). The elytra are usually dark brown or black. The head and prothorax may be the same colour or tan. The legs and antennae are tan, while the underside varies from tan to dark brown. Under the elytra is a pair of wings used for flying. The small head has a pair of compound eyes and two short antennae.

Female ladybirds lay eggs probably near infestations of prey. A larva hatches from each egg. They are covered with short hairs. The three pairs of legs are used for walking. As the larva grows, it moults (changes skin). There are four larval instars (stages). The last instar is grey on its dorsal (top) side with the short pale setae grouped on tubercles­. Some tubercles on abdominal segments 1, 5 and 6 are pale. Also there is white wax between some of the setae. The underside of the larvae is white to pale grey. The small head is brown. When the fourth larval instar is fully grown, it attaches itself to a sheltered place on a plant and moults into a pupa. The white to pale grey pupa is covered with short setae. The moulted larval skin remains at the base of the pupal abdomen. Adults hatch from pupae and mate. The length of time of each life stage depends on temperature, being shorter at higher temperatures.

Annual cycle

There have not been any detailed observations of the annual cycle of this ladybird in New Zealand. Adults and larvae have been only been found associated with insect prey in spring and summer.

Walking and flying

Both adult and larval stages of this yellow haired ladybird have three pairs of legs that can be used for walking. Adults have wings and can fly.

Feeding

The adult and larval ladybirds eat psyllids, mealybugs, aphids and scale insects. The jaws are the primarily structures used for holding and chewing the prey. Legs do not appear to be used for holding food.

Side view of adult yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2CAP]

Adult yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2CAQ]

Underside of adult yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2CAS]

Adult of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2CBA]

Adult of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2CB9]

Underside of adult of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2CBB]

Adult of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2CB8]

Small larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) on underside of Astelia banksii (Asteliaceae) leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2CB4]

Large larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) in a colony of Long-fringed Astelia mealybug, Rastrococcus asteliae (Hemiptera: Pseudococcidae) on underside of Astelia banksii (Asteliaceae) leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2861]

Larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2CAZ]

Moulted skin of larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) on underside of Astelia banksii (Asteliaceae) leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2CB6]

Larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2CB5]

Larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2CAX]

Underside of larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2CB0]

Pupa of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae), note the moulted larval skin at the base of the pupa and its white wax. Creator: Tim Holmes. © Plant & Food Research. [Image: 2CB2]

Pupa of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae), note the moulted larval skin at the base of the pupa and its white wax. Creator: Tim Holmes. © Plant & Food Research. [Image: 2CB1]

Pupa of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae), note the short yellow bristles covering the pupa. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2CBF]

Some adult yellow haired ladybirds are easily recognised by their tan coloured head and prothorax, and their short dense tan coloured setae (Hairs). For other adults, expert help is needed.

The larvae are distinctive, but because little is known about the appearance of other native ladybird larvae, larvae of the yellow haired ladybird cannot be identified with certainty. The last instar larva is grey on its dorsal (top) side with the short pale setae grouped on tubercles­. Some tubercles on abdominal segments 1, 5 and 6 are pale. Also there is white wax between some of the setae. The underside of the larvae is white to pale grey. The small head is brown.

Adult yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2CAR]

Side view of adult yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2CAV]

Adult of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2CBA]

Adult of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2CB9]

Larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2CAW]

Larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2CAY]

Larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2CBD]

No natural enemies of the yellow haired ladybird are known in New Zealand. They are probably preyed upon by birds, spiders and predatory insects.

Little is known about the prey of the yellow haired ladybird. Adults and larvae have been found four times associated with prey, the pittosporum psyllid, Trioza vitreoradiata and adults reared from the larvae that fed on the psyllid. Larvae were found on leaves of Astelia banksii with colonies of Long-fringed Astelia mealybug, Rastrococcus asteliae (Maskell, and reared to adulthood. A larva was found on a young frond of Sickle spleenwort, Asplenium polyodon, heavily infested with green fern aphids, Micromyzella filicis. The larva fed on the aphids, but was not reared. It is likely that this ladybird feeds on a wide variety of small insects. A larva was found feeding on the Spotted sixpenny scale, Ctenochiton paraviridis, but was not reared. It is likely that this ladybird feeds on a variety of small insects, especieally Hemiptera.

Large larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) in a colony of Long-fringed Astelia mealybug, Rastrococcus asteliae (Hemiptera: Pseudococcidae) on underside of Astelia banksii (Asteliaceae) leaf. Creator: Tim Holmes. © Plant & Food Research. [Image: 2CB7]

Larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) feeding on a Green fern aphid, Micromyzella filicis (Hemiptera: Aphididae) on a young frond of Sickle spleenwort, Asplenium polyodon (Aspleniaceae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2CBG]

Larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) feeding on a Spotted sixpenny scale, Ctenochiton paraviridis (Hemiptera: Coccidae) on a young leaf of pigeonwood, Hedycarya arborea (Monimiaceae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2CBH]

Larva of yellow haired ladybird, Adoxellus flavihirtus (Coleoptera: Coccinellidae) on a shoot of Kanuka, Kunzea sp. (Myrtaceae) a plant that is a host of several species of scale insects. Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2SB5]

Diverse habits of 'ladybirds'

Not all ladybirds eat insects; some feed on mites. Other species eat plant leaves and are pests especially in some tropical countries, whereas other ladybirds feed on fungi. One of these, Illeis galbula (Mulsant, 1850), from Australia, feeds on powdery mildew fungi. In New Zealand it is common on pumpkins and other cucurbits, plants that are commonly infected by powdery mildews. A plant feeding ladybird, hadda beetle (Epilachna vigintioctopunctata (Fabricius, 1775)) recently established in Auckland feeds on plants in the Solanaceae (potato family).

Chris Winks for identification of the ladybird.

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.

1 August 2018. NA Martin. Photo of larva on Kanuka shoot.