Hawaiian flower thrips

Thrips hawaiiensis


Eggs are kidney shaped. The egg shell is smooth, delicate, and pale white or yellow in color. Eggs are very small, measuring less than 22/1000 inch (550 µ) long by 10/1000 inch (250 µ) wide. They are usually laid singly in a scattered pattern, but sometimes may occur in rows alongside or beneath veins. They are partially or completely inserted into an incision made into the plant tissue by the saw-like ovipositor of the female (Lewis, 1973). Eggs hatch in 3 to 6 days, but may take as long as 20 days (Ananthakrishnan, 1984).


The first instar larvae are white or nearly transparent at first. Their small bodies consist of the head, 3 thoracic segments and 11 abdominal segments, 3 pairs of similarly structured legs and no wing buds. The duration of the first instar is about 1 to 5 days. When the first instars have doubled in size they find a protected spot and molt. The second instar larvae are white to yellow white, and have antennae that are shaped differently (Lewis, 1973).

When the second instar larvae are ready to molt into the pupal stage they usually move into the soil or litter beneath the host plant. We believe that the Hawaiian flower thrips behave in this manner. Whether it then molds a simple earthen shell lined with thin silken web (Lewis, 1973) as in other thrips species is unknown. The duration of the larval stage is between 4 to 10 days (Ananthakrishnan, 1984).


The first instars of the pupal stage are called prepupae and represent an intermediate stage between the larvae and true pupae. These individuals have wing buds (an early stage of wing development), rudimentary antennae, and do not feed or excrete. A single pupal stage follows after a molt. Pupae have developed antennae that curve back over the head. The wing pads have developed into long sheaths, and the legs and bodies have assumed adult proportions (Lewis, 1973). The entire pupal stage requires 3 to 10 days (Ananthakrishnan, 1984).


This thrips has a dark brown body, yellow legs, and brown antennae except for segments III and the base of segments IV and V which are yellow. Adults have two pairs of very slender wings fringed with long hairs that lay longitudinally over the back when not in use. The forewings are grayish-brown with a clear base. Females are about 3/50 inch (1.5 mm) long and the males are slightly smaller (Kono and Papp, 1977). Males are as common as females (Takahashi, 1936). The head is about as long as it is wide. The taxonomic classification of this species has been confusing because some individuals within a population can have seven antennal segments while others have eight (Zimmerman, 1948).

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