INTERESTING INSECTS

By N A Martin (2017)

Citrus whitefly predator

Until recently the Coleoptera genus, Cybocephalus was placed in the family Nitidulidae and the subfamily Cybocephalinae. Species in the genus are now placed in the family Cybocephalidae. The name of the species in New Zealand has yet to be determined. It may be Cybocephalus aleyrodiphagus Kirejtshuk, James & Heffer, 1997, an Australian species that feeds on Australian citrus whitefly.

This adventive beetle is a predator of whiteflies and was first found feeding on Australian citrus whitefly, Orchamoplatus citri (Hemiptera: Aleyrodidae) on a lemon tree in an Auckland garden during 2012. It also feeds on other species of whitefly living in trees, including a native species.

Conservation status: This adventive whitefly predator has only been found in Auckland. It will feed on native whitefly as well as pest species.

The following notes are based on observations in Auckland and of Cybocephalus aleyrodiphagus in Australia by Alexander Kirejetshuk and colleagues published in 1997. This tiny Citrus whitefly predator overwinters as adults. In Australia they lay eggs close to eggs of Citrus whitefly. The larvae feed on eggs and whitefly larvae. The mature larvae spin a cocoon, which on citrus trees, is covered with egg shells and empty shells of larvae and puparia. There are two generations per year in New South Wales and that appears to be the same in Auckland. The adults also feed on eggs and juvenile whiteflies.

The adults are tiny, about 1 mm long. The body is brown. In the male, the head and front of the pronotum (the first thoracic segment after the head) are yellow. The upper side of the body and elytra (wing covers) are covered in fine punctures. The colour of the underside is similar. The three pairs of legs and the pair of antennae are yellow-brown.

The eggs of the species in Australia are elongate, pale coloured and laid singly. The white larvae are covered with setae (hairs). As the larva grows it moults (changes skin). The number of larvae instars (stages) is not known. The mature larva is over 2 mm long. It spins a cocoon that may be covered with whitefly eggs and larval skins. It pupates in the cocoon. The pupa is creamy white. Just before the emergence of the adult, dark eyes can be seen.

Walking and flying

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

Feeding

The adult and larvae of the Citrus whitefly predator eat eggs and juvenile whitefly. The jaws are the primarily structures used for holding and chewing the prey. Legs do not appear to be used for holding food.

Adult male Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMR]

Adult male Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae): note the wing sticking out from the elytra (wing covers). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMP]

Adult male Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae): note the large pronotum, the first segment behind the head. Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMN]

Underside of an adult male Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMM]

Adult female Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae): note the all black head and pronotum (the first segment behind the head). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNX]

Adult female Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae): note the all black head and pronotum (the first segment behind the head). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNY]

Underside of an adult female Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNW]

Larva of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a leaf of ash, Fraxinus sp. with ash whitefly, Siphoninus phillyreae (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNA]

Larva of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a Meyer lemon leaf with juvenile Australian citrus whitefly, Orchamoplatus citri (Hemiptera: Aleyrodidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMS]

Larva of Citrus whitefly predator, Cybocephalus spescies 1 (Coleoptera: Cybocephalidae) making a cocoon on a Meyer lemon leaf with juvenile Australian citrus whitefly, Orchamoplatus citri (Hemiptera: Aleyrodidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMU]

Two images of a larva of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) making a cocoon on a Meyer lemon leaf with juvenile Australian citrus whitefly, Orchamoplatus citri (Hemiptera: Aleyrodidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMT]

Larva of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a Meyer lemon leaf constructing a cocoon with juvenile Australian citrus whitefly, Orchamoplatus citri (Hemiptera: Aleyrodidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMW]

Cocoon of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a Meyer lemon leaf with juvenile Australian citrus whitefly, Orchamoplatus citri (Hemiptera: Aleyrodidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MML]

Pupa of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) removed from its cocoon (left). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMX]

Cocoon of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) opened to show the pupa. Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMZ]

Pupa of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) removed from its cocoon (left). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MN0]

Two images of a pupa of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) removed from its cocoon. Creator: Tim Holmes. © Plant & Food Research. [Image: 2MN1]

Small larva of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) feeding on eggs of Australian citrus whitefly, Orchamoplatus citri (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNZ]

White cocoon of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a leaf of ash, Fraxinus sp. with ash whitefly, Siphoninus phillyreae (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNB]

Cocoon of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a leaf of Hawthorn with ash whitefly, Siphoninus phillyreae (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MN6]

Adult female Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae): note the all black head and pronotum (the first segment behind the head). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNY]

There is only one species of these predatory beetles in New Zealand that feed on whitefly. The brown adults are very small, about 1 mm long and can be seen in colonies of their whitefly hosts. The adults can be easily distinguished from similar-looking members of the family Clambidae by the absence of metacoxal plates.

The most distinctive feature of the Citrus whitefly predator is the presence of cocoons surround by a whitefly free area in whitefly colonies on the underside of leaves.

Adult male Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMQ]

Adult male Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae): note the large pronotum, the first segment behind the head. Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMN]

Underside of an adult male Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMM]

Adult female Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae): note the all black head and pronotum (the first segment behind the head). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNX]

Underside of an adult female Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNW]

Small larva of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) feeding on eggs of Australian citrus whitefly, Orchamoplatus citri (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNZ]

Larva of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a leaf of hawthorn with ash whitefly, Siphoninus phillyreae (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MN3]

Six cocoons of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a Meyer lemon leaf with larvae and puparia of Australian citrus whitefly, Orchamoplatus citri (Hemiptera: Aleyrodidae): note the whitefly free areas around the cocoon. Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMY]

Pupa of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) removed from its cocoon (left). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMX]

White cocoon of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a leaf of ash, Fraxinus sp. with ash whitefly, Siphoninus phillyreae (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNB]

No natural enemies of the Citrus whitefly predator have been found in New Zealand.

Both adults and larvae feed on whitefly eggs and larvae. The adults may feed on puparia. They were first found feeding on Australian citrus whitefly on a Meyer Lemon tree. They have since been found on another adventive species of whitefly and on one endemic species, Simple whitefly, Asterochiton simplex on leaves of a Pittosporum species. All hosts plants of the whitefly prey are trees.

Six cocoons of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a Meyer lemon leaf with larvae and puparia of Australian citrus whitefly, Orchamoplatus citri (Hemiptera: Aleyrodidae): note the whitefly free areas around the cocoon. Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMY]

Pupa of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) removed from its cocoon (left). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MMX]

Cocoon of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a Meyer lemon leaf with juvenile Australian citrus whitefly, Orchamoplatus citri (Hemiptera: Aleyrodidae). Creator: Tim Holmes. © Plant & Food Research. [Image: 2MML]

Larva of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a leaf of hawthorn with ash whitefly, Siphoninus phillyreae (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MN3]

Larva of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a leaf of hawthorn with ash whitefly, Siphoninus phillyreae (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MN4]

Larva of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a leaf of ash, Fraxinus sp. with ash whitefly, Siphoninus phillyreae (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MN9]

Larva of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) making a cocoon on a leaf of hawthorn with ash whitefly, Siphoninus phillyreae (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MN5]

White cocoon of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a leaf of ash, Fraxinus sp. with ash whitefly, Siphoninus phillyreae (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MNB]

Cocoons of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a leaf of Pittosporum bracteolatum with Simple whitefly, Asterochiton simplex (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MN7]

Cocoon of Citrus whitefly predator, Cybocephalus species 1 (Coleoptera: Cybocephalidae) on a leaf of Pittosporum bracteolatum with Simple whitefly, Asterochiton simplex (Hemiptera: Aleyrodidae). Creator: Nicholas A. Martin. © Plant & Food Research. [Image: 2MN8]

Kirejtshuk AG, James DG, Heffer R. 1997. Description and biology of a new species of Cybocephalus Erichson (Coleoptera: Nitidulidae), a predator of Australian citrus whitefly. Australian Journal of Entomology 36: 81-86.

Dr Richard Leschen for identification of the beetles and for helpful comments on this factsheet.

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