Brown soldier bug - Cermatulus nasalis
By N A Martin (2016)
Aelia nasalis Westwood, 1837
Asopus nummularis Erichson, 1842
Asopus binotatus Walker, 1867
Rhaphigaster pentatomoides Walker, 1867
Three subspecies are recognised in New Zealand:
C. nasalis hudsoni Woodward 1953 is present in alpine areas of the South Island of New Zealand,
C. nasalis nasalis (Westwood, 1837) is present in Australia, Timor and New Zealand,
C. nasalis turbotti Woodward 1950 is found only on the Three Kings Islands, New Zealand.
Biostatus and Distribution
This native shield bug is present in New Zealand, Australia and Timor. The Brown soldier bug is a predator that feeds on free living insects such as caterpillars. It occurs in gardens and parks as well as in native ecosystems. There are three subspecies in New Zealand.
Conservation status: One of the subspecies is restricted to the Three Kings Islands and another to alpine areas in the South Island. The third subspecies is widespread and is found in native ecosystems, in gardens and parks.
Life Stages and Annual Cycle
The Brown soldier bug overwinters as adults that shelter in secluded places. There appears to be a single generation per year with eggs being found from November to February. The overwintering adult females may be found sunning themselves in late winter and spring. Each female lays several batches of eggs. The nymphs grow into adults during summer.
The adult females are 11-12 mm long. Males are slightly smaller. The body, forewings and three pairs of legs are shades of orange-brown to dark brown with black markings and are covered with fine punctations that are usually surrounded by a ring of pale to dark brown or black. There is usually a darker patch on the forewing. The antennae are brown. On the underside there is a long rostrum that holds the stylets used for feeding.
Several clusters of eggs are laid. The clusters may small, about to 14 eggs, one for each ovariole or much larger, up to 50 eggs per cluster is possible. The black eggs have a ring of short white spines on top and are arranged in several rows on leaves or bark.
The nymphs that hatch from the eggs are like small, black, wingless adults. There are five nymphal instars (stages). Nymphs go from one stage to the next by moulting, where the “skin” on the dorsal side splits and the next stage pulls itself out. The first instar nymphs are black on top with a white or yellow patch on either side of their abdomen. The abdomen is dark reddish, almost black. The terminal portion of each antennal segment is pale reddish. The second instar is similar. The underside of the abdomen is red. The third instar nymphs have a lateral fringe of white patches on the thorax and abdomen. The second and third segments of the antennae have basal areas of orange-brown. The fourth instar is similar, but has small wing buds. Some have white bands on the tibia of the legs. The antennae of the fourth and fifth instar nymphs is the same. The first segment is short and black, the basal portion of the other three segments is red and the rest black. The red area occupies most of the long second segment. The fifth instar has larger wing buds and has more white on the top of the abdomen. The tibia of each leg has a white band. The fifth instar of the subspecies, C. nasalis turbotti, is shiny green instead of black.
Australian photos of nymphs are quite different from those illustrated here from around Auckland. Australian specimens are much redder.
The length of the lifecycle (time from egg to adult) varies with temperature and is faster at higher temperatures. In South Australian laboratory experiments, eggs developed from 15 to 30°C, taking 34 days at 15°C and 19 days at 20°C. At 20°C the five instars took 5, 10, 8, 9 and 14 days to complete development respectively.
Walking and flying
The nymphs and adults have six legs (three pairs) that are used for walking. The adults have two pairs of wings. The front pair is modified as covers for the hind wings. Part of the forewing is coloured brown, while the rest is membranous.
Like other Hemiptera, the Brown soldier bug has sucking mouth parts. The long stylets, special shaped rods, are held in the rostrum. The Brown soldier bugs are predators. The feed on free living insects such as caterpillars which they stab with their stylets, mandibles and maxillae. During feeding the insect is held by at the end of the rostrum the mandibles. The maxillae are inserted further into the prey. They form two tubes, a narrow duct down which saliva is pumped into the prey, and a larger tube up which the partly digested food is sucked.
The first instar nymph is the only stage that is not a predator. After hatching they stay by their eggs. They will drink water and it is reported that they might feed on plant juices.
There are several species of Pentatomidae in New Zealand that have brown adults. The nymphs of which are also distinctive.
The brown soldier bug, Cermatulus nasalis, is coloured shades of orange-brown to dark brown with black markings and is covered with fine punctations that are usually surrounded by a ring of pale to dark brown or black. The rounded end of the scutellum is usually pale yellow-brown. There is usually a darker patch on the forewing. The antennae are brown.
Schellenberg's soldier bug, Oechalia schellenbergii, another predator, has distinct pointed ‘shoulders’. The pale end of the scutellum is pointed.
Brown shield bug, Dictyotus caenosus is a seed feeder. It is more rounded and a uniform mid brown colour with fine dark punctures and a network of this dark lines on the forewings.
Adult Pittosporum shield bugs, Monteithiella humeralis, are mainly found on their host plants. The adults are dark brown with pale lateral areas on the pronotum. The basal half the fifth antennal segment is pale.
Fifth instar nymphs
The last nymphal stage of the brown soldier bug is mostly black and white. The lateral edge of the pronotum is white and there are white marks on the lateral edges of the abdomen. There is also a prominent white area by the wing buds. The tibia of each leg has a white band. The antennae have red on segments 2, 3, and four. The fifth instar of the subspecies, C. nasalis turbotti, is shiny green instead of black. Australian photos of nymphs are quite different from those illustrated here from around Auckland. Australian specimens are much redder.
Schellenberg's soldier bug last stage nymph is mainly black. There is a thin white lateral edge on the pronotum. On the abdomen there is prominent red area around a central black areas associated with the scent gland openings. The legs also have white bands on the tibia. The antennae are dark.
Brown shield bug last stage nymph has a dark grey-brown head and thorax. The abdomen is pale with numerous brown punctures. The areas around the scent gland openings are dark brown. The antennae are dark brown.
Pittosporum shield bugs last stage nymph is dark brown and has pale bands on the antennae. The nymphs are normally only found on host plants.
The black eggs are laid in batches of 14 to almost sixty. There are short white spines around the top of the eggs. Small batches of black eggs could be confused with parasitised eggs of other species of Pentatomidae.
Brown soldier bugs have been eaten by the reptile, Tuatara, Sphenodon punctatus. They may occasionally be eaten by birds, but the scent glands probably deter most would be predators.
Eggs of the Brown soldier bug may be parasitized by two species of tiny wasps belonging to the family Platygasteridae. Trissolcus oenone (Dodd, 1913), a native species, parasitizes several native shield bugs. Another egg parasitoid, Trissolcus basalisi (Wollaston 1858), was released into New Zealand in 1949 to control the green vegetable bug, Nezara viridula. It also parasitizes eggs of other shield bugs including the Brown soldier bug. When this wide host range was discovered in the 1960s, it was regarded as beneficial, because at that time protection of crops was regarded as more important than protecting native insects. Eggs of other pentatomid species parasitized by T. basalis turn black.
|Scientific Name||Common Name||Classification||Enemy Type||Reliability Index||Biostatus|
|Trissolcus basalis (Wollaston, 1858)||Green vegetable bug egg parasitoid (Wasp)||Hymenoptera: Platygasteridae||parasitoid||10||adventive|
|Trissolcus oenone (Dodd, 1913)||Native shield-bug egg parasitoid (Wasp)||Hymenoptera: Platygasteridae||parasitoid||10||native|
|Sphenodon punctatus (Gray, 1842)||Tuatara (Reptile)||Sphenodontiae: Sphenodontidae||predator||10||endemic|
Myers (1926) reports that adult Brown soldier bugs have been observed feeding on the nectar of Metrosideros perforate, (Myrtaceae). Careful observation may show that the adults and nymphs feed on nectar of other flowers.
The Brown soldier bug feeds on a variety of free living prey. It has often been observed feeding on caterpillars.
Like other Hemiptera, the Brown soldier bug has sucking mouth parts. The long stylets, special shaped rods, are held in the rostrum. The Brown soldier bugs are predators. The feed on free living insects such as caterpillars which they stab with their stylets, mandibles and maxillae. During feeding the insect is held by at the end of the rostrum the mandibles. The maxillae are inserted further into the prey. They form two tubes, a narrow duct down which saliva is pumped into the prey, and a larger tube up which the partly digested food is sucked. The first instar nymph is the only stage that is not a predator.
|Scientific Name||Common Name||Classification||Reliability Index||Biostatus|
|Agrotis ipsilon (Walker, 1865)||Greasy cutworm||Lepidoptera: Noctuidae||10||native|
|Caliroa cerasi (Linnaeus, 1758)||Pear and cherry slug||Hymenoptera: Tenthredinidae||10||adventive|
|Chrysodeixis eriosoma (Doubleday, 1843)||Green looper||Lepidoptera: Noctuidae||10||native|
|Ctenoplusia albostriata (Bremer & Grey, 1953)||Fleabane looper||Lepidoptera: Noctuidae||10||adventive|
|Danaus plexippus (Linnaeus, 1758)||Monarch||Lepidoptera: Nymphalidae||10||adventive|
|Epiphryne verriculata (Felder & Rogenhofer, 1875)||Cabbage tree moth||Lepidoptera: Geometridae||10||endemic|
|Gonipterus scutellatus Gyllenhal, 1833||Gum-tree weevil||Coleoptera: Curculionidae||10||adventive|
|Helicoverpa armigera (Walker, 1857)||Tomato fruitworm||Lepidoptera: Noctuidae||10||adventive|
|Homodotis megaspilata (Walker, 1862)||Small hook-tip looper||Lepidoptera: Geometridae||10||endemic|
|Lochmaea suturalis Thomas, 1866||Heather beetle||Coleoptera: Chrysomelidae||10||adventive|
|Mythimna separata (Walker, 1865)||Northern armyworm||Lepidoptera: Noctuidae||10||adventive|
|Paropsis charybdis Stal, 1860||Eucalyptus tortoise beetle||Coleoptera: Chrysomelidae||10||adventive|
|Persectania aversa (Walker, 1856)||Southern armyworm||Lepidoptera: Noctuidae||10||endemic|
|Pseudocoremia suavis Butler, 1879||Common forest looper||Lepidoptera: Geometridae||10||endemic|
|Rhodopsalta cruentata (Fabricius, 1775)||Redtailed cicada||Hemiptera: Cicadidae||10||endemic|
|Uresiphita maorialis (Felder & Rogenhofer, 1875)||Kowhai moth||Lepidoptera: Crambidae||10||endemic|
|Vanessa gonerilla Fabricius, 1775||Red admiral||Lepidoptera: Nymphalidae||10||endemic|
Why Stink bugs
Pentatomidae are often called stink bugs because when handled they emit a strong smell. The nymphs have prominent glands on the upper (dorsal) side of their abdomen, while adults have glands between the bases of their legs. The chemicals may deter predators and cause other bugs to drop to the ground, but some of the chemicals produced may also act as aggregation pheromones.
Research project 1
Do first instar nymphs imbibe surface liquid on plants and/or suck plant juices?
Research project 2
Adults have been observed feeding on nectar of one species of plant. Do they feed on other flowers and do nymphs also feed on nectar?
Awan MS. 1988. Development and mating behaviour of Oechalia schellenbergii (Guerin Meneville) and Cermatulus nasalis (Westwood) (Hemiptera, Pentatomidae). Journal of the Australian Entomological Society 27: 183-187.
Edwards PB, Suckling DM. 1980. Cermatulus nasalis and Oechalia schellembergii (Hemiptera: Pentatomidae) as predators of Eucalyptus tortoise beetle larvae, Paropsis charybdis (Coleoptera: Chrysomelidae) in New Zealand. New Zealand Entomologist. 7(2): 158-164.
Lariviere M-C. 1995. Cydnidae, Acanthosomatidae, and Pentatomidae (insecta: Heteroptera): systematics, geographical distribution, and bioecology. Fauna of New Zealand. 35: 1-107.
Myers, JG. 1926. Biological notes on New Zealand Heteroptera. Transactions and Proceedings of the New Zealand Institute. 56: 449-511.
The New Zealand Institute for Plant & Food Research Limited (Plant & Food Research) for permission to use photographs.
Anne Barrington, Plant & Food Research for specimens to photograph.