Biology and behavior of the strawberry guava sawfly, Haplostegus epimelas Konow 1901 (Hymenoptera: Pergidae), in southern Brazil

6 Pages·2000·3.1 MB·

by  J H Pedrosa-Macedo

PROC. ENTOMOL. SOC. WASH.
102(1), 2000. pp. 129-134
BIOLOGY AND BEHAVIOR OF THE STRAWBERRY GUAVA SAWFLY,
HAPLOSTEGUS EPIMELAS KONOW 1901 (HYMENOPTERA: PERGIDAE),
IN SOUTHERN BRAZIL
J. H. Pedrosa-Macedo
—
Laboratorio de Prote9ao Florestal DSM/SCA-UFPR, Av. Pref. Lothario Meissner,
3400, 80.210-170 Curitiba, Parana, Brazil (e-mail: [email protected])
—
Abstract. Results of four years of observation and study of the strawberry guava
sawfly, Haplostegus epimelas Konow 1901, in two ecosystms, coastal plain and Parana
first plateau of Brazil, are presented. The strawberry guava sawfly is trivoltine, feeding
almost exclusively on sprouting ara9a, or strawberry guava, Psidium cattleiamim Sabine
(Myrtaceae). This plant is native to the Brazihan Atlantic forest but is currently found
throughout the tropics where it is frequently a weed. Adult female sawflies are rarely
found in the field and males have never been found. The eggs are laid when the sprouts
are young. Larvae are gregarious and go through six or seven instars. Pupation occurs in
the soil. Natural enemies attack all stages. The total parasitism frequency is 3.6%, mostly
by Vibrissina sp. (Diptera: Tachinidae). Two main types of damage to strawberry guava
are oviposition wounds resulting in the death of twigs and young leaves consumed or
damaged by larval feeding. The sawfly completes its life cycle on strawberry guava but
has recently been observed feeding on commercial guava, P. guajava L., which may
preclude its use as a biological control agent.
—
Resumo. Sao apresentados os resultados de quatro anos de observa9oes e estudos
sobre a vespa-serra, Haplostegus epimelas Konow 1901 (Hymenoptera: Pergidae) em dois
ecossistemas: Litoral (Restinga) e Primeiro Planalto Paranaense. O dimorfismo sexual
entre machos e femeas e distinto por tres caracteristicas morfologicas. A vespa-serra
procria-se e alimenta-se na brota^ao sazonal do ara^azeiro, Psidium cattleianum Sabine
(Myrtaceae) e e trivoltina. Esta planta originalmente da Floresta Atlantica brasileira en-
contra-se distribuida nas regioes tropicals e subtropicais onde se tomou daninha. Femeas
adultas da vespa-serra sao raramente encontradas no campo e os machos nunca foram
vistos. Os ovos colocados em brota^oes tenras. As larvas sao gregarias e passam por 6-
7 intares. O empupamento ocorre no solo. Ha inimigos naturals em todas as fases do ciclo
vital. O parasitismo por Vibrissina sp. (Diptera: Tachinidae) atinge 3, 6%, e o mais im-
portante. Dois tipos de danos sao encontrados: lesoes nos ramos pelo ato de postura e os
danos causados nas folhas jovens por larvas neonatas. A vespa-serra completa seu ciclo
vital no ara9azeiro e foi recentemente encontrada em goiabeira, Psidium guajava L. (Myr-
taceae) fato que pode limitar o seu uso como um agente de controle biologico.
Key Words: ara^a, biological control, biology, behavior, strawberry guava, sawfly
For almost two centuries, ara9a or straw- (Myrtaceae), has attracted the attention of
berry guava, Psidium cattleiammi Sabine horticulturists who have used it as an or-
130 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
namental plant and fruit tree. It has been (2) the coastal plains of Parana and Santa
introduced into several parts of the world, Catarina (Restinga) (48°29' to 48°46'W and
where it has spread aggressively competing 25°19' to 26°03'S) especially the districts of
with the local vegetation (Smith 1985). In Antonina, Morretes, Paranagua, Pontal do
its native Brazilian Atlantic forest, it grows Parana, Guaratuba, and the coastal plain of
harmoniously with the other vegetation of Santa Catarina (only the district of Itapoa).
the woods. Two types of strawberry guava According to Carpanezzi et al. (1986), the
are known, one with red fruit and the other first plateau of Parana is characterized by
with yellow fruit. In Brazil, the red-fruited altitudes from 650 to 1,100 m, and by a rain
form is confined to higher elevations above forest of Araucaria angustifolia (Araucari-
850 m, whereas the yellow-fruited form is aceae) and submontane fields. Within the
found throughout the range. Elsewhere in Holdridge system, the climate is temperate,
the world, the two forms are found at all hot and humid, or very humid. The average
elevations. In its native woods, this tree can annual temperature ranges from 15° to
be of medium height (up to 5 m), but it has 19°C, with an absolute minimum of —10°C.
a low density per hectare (<1% cover). In One to forty frosts occur per year. The av-
mm
contrast, the trees along roads, urban areas, erage rainfall ranges from 1250 to 2500
and agricultural or pasture areas are abun- and there is no water deficit. The coastal
dant and bushy. Numerous natural enemies plains of Parana and Santa Catarina are
and competition from other plants effec- characterized by native rain forests of low
tively control strawberry guava in Brazil. altitude, ranging from to 500 m. The cli-
This study describes the biology ofHap- mate is subtropical, humid or very humid,
lostegus epinielas Konow, the associated according to the Holdridge system. The av-
phenology of strawberry guava, and the im- erage annual temperature ranges from 18°
pact of the sawfly's damage on the plant. to 22°C, with an absolute minimum of
The objective is to evaluate the potential of -0.9°C. Frosts are rare. The annual rainfall
the sawfly as a biological control agent in ranges from 1,600 to 2,000 mm, and there
Hawaii. Some other insect species, mainly is no water deficit—.
gall midges, are important natural enemies Methodology. All captured insects
of strawberry guava (Wilder 1995, Vitorino were taken to the nursery at the Forest Pro-
1995, Angelo 1997). A species of Coleop- tection Laboratory, Federal University of
tera (Chrysomelidae) is also destructive, but Parana, where they were kept alive for ob-
it is not confined to strawberry guava (Cax- servation. Prepupae were kept in containers
ambu 1998). According to Smith (1993), of two different sizes (3X7 cm, vol. 45
some Pergidae are considered forest pests ml; 5 X 11 cm, vol. 180 ml) to study aduh
in North and South America, New Guinea, and parasite emergence and to record life
and Australia. Benson (1940) and Smith history data, e.g., adult longevity, oviposi-
(1990) reported that H. epimelas also at- tion, depth of pupation, and pupal duration.
tacks guava, Psidium guajava L., in the Diameter of cocoons, period ofoviposition,
State of Pemambuco. and number of eggs were measured on
shoot tips or branches. The growth of
Material and Methods
strawberry guava was observed using 20
—
Study area. Field observations of the trees previously chosen at random and
plant and sawfly were carried out in two tagged, ten in the District of Colombo, Pa-
regions: (1) First plateau of Parana (48°58' rana (Estancia Betania), and ten from the
to 49°38'W; 25°27' to 25°35'S), particularly District of Piraquara, Parana (Mananciais
the districts of Curitiba, Balsa Nova, Cam- da Serra Mar). The presence of adult saw-
po Largo, Almirante Tamandare, Colombo, flies, eggs, and larvae were counted and ob-
Piraquara, and Sao Jose dos Pinhais; and served from September 1994 through July
VOLUME NUMBER
102. 1 131
1998. Standard statistical tests were used. Necrotic
Damage caused by oviposition and larvae F^ggs bark
Petiole Septum
were evaluated during a year of observa-
tions and collecting of field data.
Results and Discussion
—
Host plants and host specificity. In the
states of Parana and Santa Catarina, Hap- 0Stem
lostegus epimelas was observed on yellow-
(350) and red-fruited (25) strawberry guava Fig. 1. Oviposition site of Haplostegus epimelas.
Eggs are distributed symmetrically and reclined.
plants during weekly visits to the field and
in the University gardens. The red-fruited
trees are not found in the coastal plains. In ing that they move to otherbranches to con-
the two states cited above, there are several tinue oviposition. The eggs are rod-shaped,
other Myrtaceae, such as Psidiwn spathu- with ovoid tips. Eggs are white from ovi-
latiim Mattos, Campomanesia xanthocarpa position to eclosion. In the field, incubation
Berg., Eugenia uniflora L., Eugenia invol- lasts from 7 to 12 days with an average of
ucrata DC, Myrciaria trunciflora Berg., 10 days (Fig. 2).
Gomidesia schaueriana Berg., and Acca The gregarious, newly hatched larvae
sellowiana (Berg.) Burret. Sawfly eggs and move to young, recently expanded leaves to
larvae were not found o—n any ofthese trees. feed. Initially, they feed by scraping the un-
Sawfly life history. The female aver- der surface of the leaf. Fourth instar larvae
ages 10.2 ± 0.3 mm long (n = 13) and the consume the entire leaf. In the last instars
male 8.3 ± 0.3 mm long (n ^ 15). Both they remain gregarious, but they sometimes
the male and female are black dorsally with split up into smaller groups. When larvae
the ventral part of the head and the poste- are disturbed they bend the posterior part of
rior part of the abdomen dark brown, the their abdomen over their dorsum showing
thorax orange, and the front legs orange to an attitude of intimidation. If they are
the tibiae with the tarsi almost black. The touched, they regurgitate a drop of fluid
female is larger than the male; otherwise, which hangs from their mouths. The smell
the usual sexual characters separate them. of the regurgitated substance is strong and
In the field, the female is rarely observed similar to the smell of the host tissue on
on the plant, and males were never seen. To which they are feeding. Presumably, the flu-
oviposit, the female turns upside down on id deters natural enemies. The growth ofthe
young, soft branches to lay eggs. The di- larvae and the number of instars are not al-
ameter of these branches range from 2.1 to ways homogeneous. Observations in the
3.9 mm (2.9 ± 0.1 mm) (n = 61). Ninety laboratory show that the gregarious habit of
egg masses on 20 strawberry guava trees the larvae is vital for the survival of the
were observed. Only eight females were larval colony. When a group of first instar
observed during oviposition. The eggs are larvae is smaller than ten, they die before
laid in a line, under the epidermis ofyoung completing their larval development. Lar-
shoots that are slightly reclined. Between vae were observed to go through 6 or 7
each egg, there is a septum, a fiber filament instars. Growth of some larvae are delayed
of the vegetable tissue, which separates in relation to others from the same egg
them (Fig. 1). batch. As a consequence, they go through
The number of eggs laid varies from 52 at least one additional instar. When they
to 118, averaging 90.5 ± 16.4 per female reach the end of the larval period, the lar-
(n = 13). As many as 178 eggs were found vae are 22.1 ± 0.7 mm long (n =15). They
in the ovary of one virgin female, suggest- stop feeding and start draining their diges-
132 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
VOLUME NUMBER
102, 1 133
1'' Cycle 2"" Cycle 3^" Cycle Overwinter
October December January March May June July September
Fig. 3. Annual seasonal activity oiHaplostegus epimelas. 1997 to 1998.
cophagidae (Diptera). These parasites sprouts can be seen, but in winter they are
emerge from the cocoon after an average of scarce. Therefore, there are sprouts on the
28.3 ± 0.9 days (n = 12) after pupation of strawberry guava which enable the survival
the host. The percentage of parasitism re- of sawflies in all four seasons of the year.
corded was 3.6% (n = 330). Nevertheless, in the coast and plateau re-
One mite egg predator was observed. Its gions, there was a period of 120 ± 7.9 days
presence was recorded in November 1997 (n = 3, June 1995 to July 1998) in which
at Mananciais da Serra, Piraquara, Parana. no adult sawflies, eggs, or larvae were
One female adult sawfly was found caught found.
—
in a spider web. The fungi Fusarium sp. Use as a biological control agent. The
and Verticillium sp. were isolated from pupal phase of Haplostegus epimelas is
dead prepupae, but it is not known if they easy to transport or export. A 45 ml capac-
(3X7
were respon—sible for deaths. ity container cm) is adequate for
Damage. Three types of damage are handling and exporting pupae. The natural
caused by the sawfly on young shoots of enemies of the sawfly contribute to their
strawberry guava. The first and most im- population balance, but they do not limit
portant for biological control is the wound the impact and damage caused to the plant.
caused by the female during oviposition. Unfortunately, the sawfly has recently been
The second is by the young larvae (first to observed attacking two plants of Psidium
third instars) which scrape the underside of guajava. This observation, though perhaps
young and soft leaves on the same sprout an unusual even, may curtail an attempt to
as the egg mass. The third is by the fourth use this species as a biological control
to seventh instar larvae which eat mature agent.
leaves entirely elsewhere on the plant. The
Acknowledgments
female destroys the soft tissue ofthe shoots
when penetrating their epidermis with her 1 thank Dr. Clifford W. Smith, Depart-
saw-like ovipositor. The action ofthe young ment of Botany, University of Hawaii at
larvae further injures the young shoots re- Manoa; Dr. David R. Smith, Systematic En-
sulting in the death of 31% of the shoots tomology Laboratory, USDA, National
(28 of 89 observations) leaving 69% of the Museum of Natural History, Washington
shoots alive. When the first and second D.C.; Dr. Alvaro Figueiredo, EMBRAPA/
types of damage occurred together, they Colombo, Parana; the biologist Ronaldo
caused irreparable loss to the strawberry Toma, the designer Ricardo Pedrosa Ma-
guava, which survived but had permanent cedo, the administration of SANEPAR in
damage, i.e., the branches were bent. Piraquara, the Estancia Betania in Colom-
The activity of the sawfly is synchro- bo, and all the members of the research
nized with flushing ofthe strawberry guava. group on biological control of plants of the
The sprouts on the branches are abundant Laboratory of Forest Protection of the De-
in the spring and summer. In autumn, new partamento Silvicultura e Manejo-SCA-
— — —
134 PROCEEDINGS OF THE ENTOMOLOGICAL SOCIETY OF WASHINGTON
UFPR, for their suggestions and contribu- de Posteres. Rio de Janeiro 24-28 de maio de
tions. Finally, I thank Dr. Peter W. Price, 1998.
Smith, C. W. 1985. Impact ofalien plants on Hawaii's
Northern Arizona University, Flagstaff, for
native biota, pp. 180-250. In Stone, C. P. and J.
reviewing the manuscript. M. Scott, eds. Hawaii's terrestrial Ecosystems:
Preservation and Management. Cooperative Na-
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