Fruit Fly Expert Identification System and Systematic Information

Norrbom Status of Knowledge 35
larly modified labella) are unusual in being able to rasp and
feed on plant tissues (Driscoll & Condon 1994, Condon &
Norrbom 1994). In many fruit flies, both males and females
have a premating development period of a week or more during
which they do not mate (Steck 1981, Landolt 1984, Williamson
1989).
The appearance of some Tephritidae (e.g., Toxotrypana,
some Anastrepha, some Pseudophorellia, various Adramini
and Dacina) strongly suggests that they are wasp mimics, and
at least in T. curvicauda this is reinforced by behavior (Knab
& Yothers 1914). Other fruit flies with banded wings and/or
spotted abdomens may be jumping spider mimics (Hasson
1995).
Many fruit flies mate on their host plants, but mating tactics
vary, even within some species. Lek formation by males, usually
on nonhosts, has been observed in Ceratitis capitata and
species of Dacina, Anastrepha, Rhagoletis, and Procecidochares
(Prokopy & Hendrichs 1979, Dodson 1986, Sivinski &
Burk 1989, Aluja 1994). Males of most species of Tephritidae
that have been studied secrete some type of sex-attractant
chemical, either by inflating the lateral abdominal membranes
or by extruding an anal pouch (Pritchard 1967, Headrick &
Goeden 1994). They disperse these pheromones by wing fanning,
which also produces sounds of possible significance in
courtship (Sivinski & Webb 1985[4490], Mankin et al. 1996).
Males of many species of Bactrocera and Dacus have specialized
structures, including a tibial pad, a microtrichose area of
the wing, and a row of setae on the abdomen called the pecten,
which are used for pheromone dispersal (I.M. White, pers.
comm.). The pecten has been proposed as a stridulatory organ
(Monro 1953, Kanmiya 1988). In Anastrepha robusta, the
calling behavior includes short looping flights (Aluja
1993[107]). Visual stimuli, as well as chemical and auditory
stimuli, play an important role in communication between and
among the sexes and with other insects. The body, which is
often brightly colored, and the wings, which are usually patterned
and are often held or moved in particular ways, no doubt
act as releasers. Males of some species engage in antagonistic
displays or bouts (Boyce 1934, Landolt & Hendrichs 1983,
Headrick & Goeden 1994), including species of Phytalmia
which have large genal processes used in these bouts (Moulds
1977). Mate-guarding and male defense of food resources attractive
to females also have been reported (Hendrichs & Reyes
1987, Headrick & Goeden 1994, Opp et al. 1996).
Courtship can be elaborate in some species, or simple and
brief in others. Headrick & Goeden (1994) defined 14 movements
or behaviors that commonly occur in courtship, which
may include various types of body, leg, and wing movements,
and/or transfer of a “nuptual gift” (trophallaxis). The latter
behavior has been observed in diverse taxa, including species
of Dirioxa (Acanthonevrini), Anastrepha (Toxotrypanini), and
various genera of Tephritinae (Freidberg 1986, Aluja, Jacome
et al. 1993, Headrick & Goeden 1994). The gift may be passed
before or after copulation, and it may consist of liquid transferred
by direct contact of the mouthparts (Freidberg
1982[1557], Aluja, Jacome et al. 1993) or may be a solidified
froth deposited on the substrate (Stoltzfus & Foote 1965,
Pritchard 1967, Novak & Foote 1975, Freidberg 1981[1555],
Jenkins 1990). Copulation is determined by female choice
(Headrick & Goeden 1994) and may last from several minutes
to several hours or more.
Oviposition behavior appears to be much more uniform
than epigamic behavior and consists of the following stages: a)
movement towards and arrival at the oviposition site; b) testing
the site; c) drilling with the ovipositor; and d) oviposition. In
the case of Anastrepha grandis, which lays a large batch of eggs
in a tough, thick-skinned fruit, this process may last many hours
(Silva 1991). Species in five genera have been reported to
deposit a marking pheromone that deters oviposition by other
females (Prokopy et al. 1976, Averill & Prokopy 1989[247],
Straw 1989[4692]). This involves the female dragging her
aculeus over the substrate, secreting and smearing the pheromone.
In the case of Rhagoletis cerasi, the pheromone has been
identified, synthesized, and used in orchards to combat damage
to cherries (Aluja & Boller 1992).
Host plants
Most species of Tephritidae whose biologies are known
are phytophagous. Host range varies considerably, often among
closely related species (Norrbom & Kim 1988[15085], Goeden
1992, 1993, 1994). Many species are strictly monophagous, for
example, Bactrocera oleae, which breeds only in olives, but
some pest species are remarkably polyphagous, for example,
Ceratitis capitata, which has been reported from more than 300
hosts (Liquido et al. 1991). Probably the majority of Tephritidae,
however, are oligophagous, breeding in a few related or
ecologically and chemically similar hosts. Toxotrypana species,
for example, breed in similar, latex-bearing, thick skinned
fruits of Caricaceae and Asclepiadaceae, two plant families that
are not closely related. Even many of the polyphagous pest
species, although able to breed in many hosts, have preferences
for certain plant families or genera (Hernández-Ortiz & Aluja
1994). Host races are known in at least two genera (see “Cryptic
species and host races”).
Although phytophagy is the predominant mode of feeding
in the Tephritidae, some Phytalmiini and Acanthonevrini are
saprophagous. A few species have been reared from rotting
fruit, decomposing tree trunks, or from under bark of live trees
(Munro 1967[3521], Hardy 1986[1962], Dodson & Daniels
1988, Permkam & Hancock 1995[3795]). Termitorioxa termitoxena
has been reared from termite colonies (Hill 1921), and
species of Acanthonevra breed in decaying bamboo shoots
(Hancock & Drew 1995[1902]). Saprophagy, which is predominant
in the Platystomitidae and Ulidiidae, could be the
primitive feeding habit for the Tephritidae.
Although tephritids are commonly known as fruit flies, a
variety of host parts and tissues are attacked, including fruits
(pulp and/or seeds), flowers, stems, buds, leaves, and roots. In
phytophagous species, females deposit eggs in healthy plant
tissue, where the larvae feed, sometimes causing gall formation.
Fruits and flowers (of diverse plant families) are the plant
parts most commonly attacked, but many Trypetini are leaf or
stem miners, and some Gastrozonina and Acanthonevrini breed
in bamboo shoots (Hardy 1986[1962], 1988[1964], Hancock &
Drew 1995[1902]). The members of the subfamily Tephritinae
have specialized in attacking Asteraceae and a few other families
(Acanthaceae, Goodeniaceae, Lamiaceae, Verbenaceae).
They breed in the flower heads or form galls, although the type
and stage of flower tissue attacked varies (Zwölfer 1988,