DRAFT

 Citrus Swallowtail
Namibian crop pests  #  51

(Princeps demodocus demodocus)  Order: Lepidoptera Family:  Papilionidae

 
 
Young caterpillar
Caterpillar in the final stage
 
Adult Citrus Swallowtail
 
 

Common names: 

Orange dog (the caterpillar) (English) 
No local common names were recorded.

Pest status:

The citrus swallowtail is widespread in Namibia and found in most gardens and fields. It does not cause economical damage to fully grown trees but is known to damage young seedlings in the nursery. 

Description:

The eggs are laid singly on the citrus leaves. They are about one millimeter in dimameter and white. 
 
The young caterpillar has spikes and a pattern of brown, black and white coulouring that makes it look like a birds dropping. it grows to 1-1.5 cm before changing into the green type of caterpillar.
 
The older caterpillar grows to a size of 3-4 cm and changes colour to green with white or pinkish markings. There are also eye markings on the front part. When the caterpillar is disturbed or scared, it sends out two orange "antennae" that are intended to scare away enemies. These "antennae" also emits a bad smell. They are withdrawn again once the scare is over.

When the caterpillar comes to maturity, it fastens itself to a citrus branch and slowly change into a pupae. The butterfly may emerge after a week or so, depending on the temperature and humidity.

The butterfly is a large swallowtail with black and yellow markings and red/blue eye spots on the hindwings. It flies all year round in gardens and fields and frequents flowers or lays eggs on citrus trees. During flight it looks more yellow than black.
 

Control:

Control is only recommended for seedlings and very small citrus trees. The young caterpillars can easily be found and handpicked from the seedlings and destroyed. In all other cases you should just leave the caterpillar as you found it and enjoy its sheer beauty. 

At Onankali Nursery in Oshikoto region, the citrus seedlings are under constant attack by swallowtail caterpillars. The workers regularly inspect the seedlings and handpick the young caterpillars. No chemical control was ever needed. 

Other notes:

The swallowtail is very easy to hatch in captivity and is large and visible. It is therefore very suitable for biology classes that can hatch them in the classroom and learn about its life cycle. The class thereby gets first hand experience of the life cycle of all butterflies and moths. The learners only need access to a citrus tree for fresh fodder and for instance a large glass container or an aquarium.  
 
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