Protaetia fusca

Pest

Common name(s)

mango flower beetle, Asian mango flower beetle

Taxonomy

Family: Scarabaeidae Subfamily: Cetoniinae Genus: Protaetia Species: Protaetia fusca (Herbst, 1790)

DNA barcode

DNA barcode available: specimen information

Adult diagnosis

Total body length 12.0–17.0 mm (0.47–0.67 in). Body broad oval; dorsoventrally flattened. Color dull, dark grey-brown to black, rarely metallic/shiny greenish; elytra with distinct pale markings (may be lost in worn specimens). Clypeus broad, anterior margin entire or sinuate. Front tibia of male with 2 external teeth (rarely with small basal tooth); female with 3 distinct external teeth. Hind tibia with single lateral ridge. Elytra of male with apical spines, female lacking spines.

Larval diagnosis

(Simpson, 1990): Like other Protaetia species, when alive, larvae crawl on their backs with their legs up, and they feel distinctly "squishy" rather than firm (a characteristic of coconut rhinoceros beetle [Oryctes rhinoceros] larvae). Grub C-shaped, not hump-backed, cylindrical, whitish. Maxilla with galea and lacinia fused, or nearly so. Clypeus with posterior row of 4 setae, 1 seta anteriorly at each margin. Labrum symmetrical; 1 large lateral seta posteriorly, 2 pairs of smaller setae centrally, 1 large anterolateral seta, apex with 8 setae, group of 3 smaller setae either side of apex. Terminal segment of antenna with 2 dorsal and 3 ventral spots. Claws of third leg large and cylindrical, with 5–8 hairs. 9th and 10th abdominal segments fused. Anal opening transverse, straight to slightly curved, palidium present.

Native range

Southeastern Asia. This beetle occurs across a vast stretch of the Indo-pacific region, occurring from India through China and southern Japan, into Indochina, the East Indies, and northern Australia (Woodruff, 2006). It is adventive in Florida, parts of the West Indies, Fiji, and Mauritius (Woodruff, 2006).

Plant host(s)

Like other Protaetia species, P. fusca is a generalist, with adults feeding upon the nectar, pollen, fruit, and sap of a number of plant species. Avocados (Persea americana), domestic roses (Rosa spp.), and peaches (Prunus persica) are attacked in Australia (Simpson, 1990). Elsewhere, African rattlebox (Crotalaria saltiana), bean tree (Cassia brewsteri), candle flower (Cassia alata), citrus (Citrus spp.), coconut palm (Cocos nucifera), corn (Zea mays), guava (Psidium guajava), longan (Dimocarpus longan), lychee (Litchi chinensis), mango (Mangifera indica), orange jasmine (Murraya paniculata), pigeon pea (Cajanus cajan), poinciana tree (Delonix regia), solitaire palm (Ptychosperma elegans), and yellow ginger (Hedychium flavescens) are all recorded as hosts (Woodruff, 2006), though almost any nectar producing or commercial fruit bearing plant is likely at risk. Larvae are compost feeders and not known as plant pests (Simpson, 1990).

Life history

In Australia, both adults and larvae are found throughout the year. Females deposit as many as 147 eggs in humus during their 6–7 month adult lifespans. Larvae feed on organic materials within the soil rather than live plant roots and reached maturity in roughly 50 days. Natural enemies include wasps (Scolia spp.) that attack larvae, a variety of birds, and Aspergillus fIavus (a fungus that sometimes infects adults).

Pest potential

Significant. This species is a known and widespread pest. Beyond its native range, Protaetia fusca has spread widely and is known from the Bahamas, Barbados, Fiji, Florida, Guam, Hawaii, and Mauritius (Woodruff, 2006). Specimens are recorded from the Cook Islands (McCormack, 2007). Throughout its distribution, the beetle damages a wide range of plants, feeding on foliage, petals, nectar, pollen, and fruit. Beetles often damage flowers when foraging for nectar and pollen, sometimes completely severing the blossom (Woodruff, 2006). Destruction of the flower can reduce the abundance of fruits that the plant will later bear. Although this species prefers already damaged or overripe fruits, fruits may be damaged (as is case in some related Protaetia species) (LeBlanc et al., 2013). Interestingly, there are records of this beetle invading commercial bee hives for honey (Woodruff, 2006).

Status in Hawaii

Established. Protaetia fusca is found on all the major islands of Hawaii (Nishida, 2002). It occurs in both urban and rural areas where it can be common. It first arrived in the state in 1949 (Woodruff, 2006).

Status in Guam

Established. This species is established on Guam, with the earliest published record dating from 1954 (Pemberton, 1954).

Potential distribution and dispersal pathway

Protaetia fusca has already spread from Hawaii to the U.S. mainland. The beetle was first recorded in Florida in 1982 when it was found in moss around the roots of a Madagascar dragon tree (Dracaena marginata) imported from a nursery in Hawaii. A number of specimens were found in South Florida in the following years, often on or near citrus plants (Woodruff, 2006), and the species is now regarded as established (Thomas, 1998). There are reliable reports of this species from the Caribbean nations of Barbados and the Bahamas (Woodruff, 2006). Further, a number of specimens have been intercepted in the state of California (Gaimari, 2005). These specimens were found in cargo from Hawaii (Woodruff, 2006). While it is not clear if this beetle can survive winters in most of the contiguous U.S., it appears likely that this species will reach Puerto Rico and the U.S. Virgin Islands in the future. In addition to cargo and nursery stock, it is possible that this species might be transported in commercially exported fruit, given its frugivorous habits.

Similar species

This beetle is one of the three members of the genus Protaetia known from Hawaii and Guam. The remaining two species are Protaetia orientalis and Protaetia pryeri. These three species are separated by size (P. fusca 12.0–17.0 mm [0.47–0.67 in] versus P. orientalis and P. pryeri that are both over 19.0 mm [0.75 in]), examination of the elytral apices (P. fusca with apical spines in the male versus P. orientalis and P. pryeri always without apical spines), and hind tibia (P. fusca with single lateral ridge versus P. orientalis with two ridges).

Other names (synonyms)

Cetonia atomaria Fabricius, Cetonia fictilis Newman, Cetonia fusca Herbst, Cetonia mandarina Weber, Heteroprotaetia fusca Miksic, Protaetia bourgoini Paulian, Protaetia mandarinea Burmeister, Protaetia taiwana Niijima and Kinoshita

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Protaetia fusca female; photo by E.L. Engasser

Protaetia fusca female; photo by E.L. Engasser

Protaetia fusca female; photo by E.L. Engasser

Protaetia fusca female; photo by E.L. Engasser

Protaetia fusca male, color morph; photo by E.L. Engasser

Protaetia fusca male, color morph; photo by E.L. Engasser

Protaetia fusca female, color morph; photo by E.L. Engasser

Protaetia fusca female, color morph; photo by E.L. Engasser

Protaetia fusca male elytra spines; photo by E.L. Engasser

Protaetia fusca male elytra spines; photo by E.L. Engasser

Protaetia fusca female elytra, lacking spines; photo by E.L. Engasser

Protaetia fusca female elytra, lacking spines; photo by E.L. Engasser

Protaetia fusca male genitalia, caudal view; photo by E.L. Engasser

Protaetia fusca male genitalia, caudal view; photo by E.L. Engasser

Protaetia fusca male genitalia, lateral view of left side; photo by E.L. Engasser

Protaetia fusca male genitalia, lateral view of left side; photo by E.L. Engasser

Protaetia fusca male genitalia, lateral view of right side; photo by E.L. Engasser

Protaetia fusca male genitalia, lateral view of right side; photo by E.L. Engasser

Protaetia fusca feeding on fallen papaya fruit by day in Hawaii; photo by E.L. Engasser

Protaetia fusca feeding on fallen papaya fruit by day in Hawaii; photo by E.L. Engasser

Protaetia fusca adult on foliage in Hawaii; photo by C. Campora

Protaetia fusca adult on foliage in Hawaii; photo by C. Campora

distribution map for Protaetia fusaca

distribution map for Protaetia fusaca