﻿Mealybugs (Hemiptera, Coccomorpha, Pseudococcidae) on parasitic plants (Loranthaceae) in Indonesia with description of a new species and a new country record

﻿Abstract Parasitic plants have been known to be attacked by insect pests since ancient times. However, little is known about the mealybug (Hemiptera, Coccomorpha, Pseudococcidae) fauna associated with them. A series of surveys of mealybugs found on Loranthaceae, a semi-parasitic plant family, was conducted in several places in Bengkulu Province, southern Sumatra, Indonesia. In the study, 55 mealybug specimens were collected, consisting of eight species belonging to five genera, namely Chorizococcus McKenzie (1 species), Dysmicoccus Ferris (2 species), Ferrisia Fullaway (1 species), Planococcus Ferris (3 species) and Pseudococcus Westwood (1 species). Chorizococcusozeri Zarkani & Kaydan, sp. nov. is new to science, whilst Planococcusbagmaticus Williams represents the first record in Indonesia. In addition, the mealybugs Dysmicoccuslepelleyi (Betrem), Dysmicoccuszeynepae Zarkani & Kaydan, Ferrisiadasylirii (Cockerell), Planococcuslilacinus (Cockerell) and Pseudococcusjackbeardsleyi Gimpel & Miller are newly recorded from plants of the family Loranthaceae. Figures and illustrations of mealybug species with a taxonomic key to Asian Chorizococcus and a new country record based on morphological characters are also updated.


Introduction
Loranthaceae is a primitive family of parasitic plants which are photosynthetic xylem feeders and cannot exist independently of the host plant (Musselman and Press 1995). Parasitic plants often severely reduce agricultural plant production, which impact the plant community (Press and Phoenix 2005). Their productivity and populations are therefore co-dependent on both the quality of the plant hosts that they parasitize and the strength of competition from neighboring plants (Pennings and Callaway 2002). In addition, a decrease in the quality of the host plants will affect organisms at other trophic levels such as herbivores and pollinators, and ultimately also affect the conditions of the abiotic environment, including having an impact on the nutrient cycles, groundwater relations, local temperature, and atmospheric CO 2 concentrations (Press and Phoenix 2005).
Just as non-parasitic plants have been attacked by insect pests for many generations, parasitic plants have also been known to be attacked by insect pests since ancient times. However, little information about the mealybug fauna (Hemiptera, Coccomorpha, Pseudococcidae) associated with parasitic plants is known. According to the scale insect database ScaleNet (url:scalenet.info/), 18 species of mealybugs (Hemiptera, Pseudococcidae) have been reported to be associated with Loranthaceae worldwide, namely Anisococcus parasitus Williams thaceae, namely C. insolita, D. debregeasiae, E. hispidus, P. bendovi, and P. viburni (García-Morales et al. 2016;Zarkani et al. 2021Zarkani et al. , 2022Sartiami et al. 2022).
For decades, the study of parasitic plants focused mainly on genetic variability, chemical contents, and their impact on their host plants. In this study we report several species of mealybugs found on Loranthaceae in Indonesia and provide an updated list of parasitic plant-feeding scale insects in the world. These specialized pests could be evaluated as natural control agents of parasitic plants in the future.

Materials and methods
Adult mealybug females were collected from a series of sampling occasions on leaves, trunk, and branches of Loranthaceae trees in Bengkulu Province, southern Sumatra, Indonesia from March to December 2022. The sampling sites are at an altitude of 0-1100 m above sea level. The specimens were mounted and preserved in slides and identified to genus level. The slide mounting was carried out under a binocular dissection microscope, LEICA EZ4HD by using the method described Kosztarab and Kozár (1988).
Species identifications were made by observing the specific features of the mealybug species using a phase-contrast compound microscope (LEICA DM2700) and were identified using the keys in Williams and Watson (1988), Williams and Granara de Willink (1992) and Williams (2004). The morphological parameters used are those used by Williams and Granara de Willink (1992), Williams (2004) and Zarkani et al. (2023). The body width and length were measured in mm which is the largest transverse measurement perpendicular to the longitudinal axis and the longest longitudinal, respectively. Other measurements are given in μm in which the standardized measurements of anatomical features, for example, antennal segments, leg segments, anal ring, pores are given. Antennae length is the sum of all segments of the antennae. Leg length is the sum of the lengths of the trochanter + femur, tibia + tarsus, and claw. In the taxonomic illustrations, the dorsal morphology is shown on the left side whilst the ventral morphology is shown on the right side. Type specimens of the genus and species described are deposited in the Mealybugs Museum, Department of Plant Protection, Faculty of Agriculture, University of Bengkulu, Bengkulu, Indonesia (MMUB).

Results and discussion
A series of surveys carried out in southern Sumatra on Loranthaceae resulted in the collection of 55 mealybug specimens consisting of eight species belonging to five genera. The identified species belong to the genera Chorizococcus McKenzie (1 species), Dysmicoccus Ferris (2 species), Ferrisia Fullaway (1 species), Planococcus Ferris (3 species) and Pseudococcus Westwood (1 species). One species is new to science, Chorizococcus ozeri Zarkani & Kaydan, whilst another, Planococcus bagmaticus Williams is a newly recorded in Indonesia. In addition, this is the first report of the genus Chorizococcus attacking Loranthaceae worldwide. Furthermore, the mealybugs Dysmicoccus lepelleyi (Betrem), Dysmicoccus zeynepae Zarkani & Kaydan, Ferrisia dasylirii (Cockerell), Planococcus lilacinus (Cockerell) and Pseudococcus jackbeardsleyi Gimpel & Miller were found for the first time associated with Loranthaceae in the world.
Currently, a total of 18 mealybug species (Hemiptera, Pseudococcidae) have been reported on plants of the family Loranthaceae worldwide (García-Morales et al. 2016); hence within this study, the number of mealybug species on these parasitic plants is increased to 26 species. The species marked with an asterisk (*) below are recorded for the first time from Indonesia. Furthermore, the species that are new host records on Loranthaceae worldwide are indicated with a plus mark (+).
Genus diagnosis. (adapted from Williams, 2004). Body of adult female membranous, varying in shape from elongate oval with almost parallel sides, to broadly oval. With 1-5 pairs of cerarii present on posterior segments of abdomen and sometimes a pair on head also, each cerarius bearing 2 conical setae; auxiliary setae absent from cerarii anterior to anal lobe pair. Oral rim ducts, sometimes of 2 sizes, present on dorsum and frequently also on venter. Oral collar tubular ducts usually present, at least on venter; if present on dorsum, then restricted to margins. Antennae each normally with 7 or 8 segments. Legs well developed, with translucent pores usually present, at least on hind coxae. Claw normally stout, without a denticle. Tarsal digitules minutely knobbed. Multilocular disc pores present on venter, rarely found on dorsum. Circulus present or absent, when present usually divided by an intersegmental line. Anal ring normal, bearing 6 setae. Anterior and posterior ostioles present.   lengths for each posterior leg: coxa 125-175 μm, trochanter + femur 237.5-307.5 μm, tibia + tarsus 225-300 μm, claw 25.0-27.5 μm. Ratio of length of tibia + tarsus to trochanter + femur, 0.95-0.98: 1; ratio of length of tibia to tarsus, 1.81-2.16: 1; ratio of length of trochanter + femur to greatest width of femur, 3.8-4.39: 1; coxa with translucent pores, femur and tibia without translucent pores. Tarsal digitules capitate, each 37.5-50.0 μm long. Claw digitules capitate, each about 20.0-22.5 μm long. Both pairs of ostioles present, anterior ostioles each with a total for both lips of 6-11 trilocular pores and without setae; posterior ostioles each with a total for both lips of 6-9 trilocular pores and without setae. Anal ring about 80.0-87.5 μm wide, bearing 6 setae, each seta 87.5-100.0 μm long.
Comments. Chorizococcus ozeri is most similar to Chorizococcus srinagaricus Williams in having no oral rim tubular ducts on the venter; dorsal rim tubular ducts few, present mainly either in medial areas or marginal areas. However, C. ozeri can be distinguished from C. srinagaricus in having (character states for C. srinagaricus given in parentheses): (i) oral rim tubular ducts present mainly in marginal areas of dorsum (mainly in medial areas of dorsum); (ii) oral collar tubular ducts absent on dorsum (present); (iii) ventral oral collar tubular ducts present around abdomen only (present on entire body surface); (iv) large discoidal pores absent from venter (present); and (v) translucent pores on hind coxa present (absent).
It is also similar to Chorizococcus sorgi Williams in lacking oral collar tubular ducts entirely from ventral margins of head and thorax; multilocular disc pores and oval collar tubular ducts absent from the area lateral to each first coxa. However, C. ozeri can be distinguished from C. sorgi in having (character states for C. sorgi given in parentheses): (i) cerarii confined to anal lobes only (present on at least 3 posterior cerarii); (ii) no oral rim tubular ducts on venter (oral rims present on venter); and (iii) multilocular disc pores in two rows on venter (in one row).

Planococcus bagmaticus Williams* +
Comments. The holotype and paratypes specimens were recorded from Nepal, all in a single slide and deposited at Entomological Institute, Hokkaido University, Sapporo, Japan (HUSJ) and Natural History Museum, United Kingdom, London (BMNH), respectively. It was originally recorded from Trachelospermum sp. (Apocynaceae) (Williams 2004). This is the second report of the species after Takagi collected the species from Kathmandu Valley, Bagmati, Godavari-Nepal in 1975 (Williams 2004). It is the only known species of Planococcus in southern Asia with dorsal multilocular disc pores. The species is closed to Pla- nococcus epulus De Lotto described from Kenya which also has dorsal multilocular disc pores, but P. epulus possesses dorsal transverse rows of oral collar tubular ducts, whereas in P. bagmaticus, all dorsal oral collar tubular ducts are restricted to small lateral groups on abdominal segments VI and VII. The species was sometimes found mixed with specimens of P. jackbeardsleyi.