ArticlePDF Available

Combining molecular and morphological approaches to differentiate the pest Costelytra zealandica (White) (Coleoptera: Scarabeidae: Melolonthinae) from the non-pest Costelytra brunneum (Broun) at the larval stage

Authors:

Abstract

The frequently strong morphological similarities that exist between the larvae of congeneric scarab beetles are likely to lead to misidentification of field-collected specimens of sympatric species. This is the case for the New Zealand endemic pasture pest Costelytra zealandica (White, 1846) (Scarabaeidae: Melolonthinae) and the closely related non-pest species C. brunneum (Broun, 1880), where a taxonomic key is only available for the first of them and does not allow the distinction between the two species. Mistaken identification and sampling of such fundamentally different organisms during ecological and / or behavioural studies could to lead to invalid interpretations and misinformed decisions in the establishment of pest control programmes. Molecular-based species identification is nowadays recognised as an effective way.
A preview of the PDF is not available
... C. giveni and Wiseana spp.) have adapted to New Zealand's nutrient-rich exotic pastures causing severe and persistent damage (Ferguson et al. 2018). Further, even though closely related to C. giveni, C. brunneum (Broun) has not made the transition into the exotic pastures (Lefort et al. 2013). Lefort et al. (2013) found that C. giveni has a preexisting ability to tolerate plant defence chemicals that C. brunneum does not have and this explains why C. giveni has become a serious pest of pasture throughout New Zealand (Lefort et al. 2015a,b). ...
... Further, even though closely related to C. giveni, C. brunneum (Broun) has not made the transition into the exotic pastures (Lefort et al. 2013). Lefort et al. (2013) found that C. giveni has a preexisting ability to tolerate plant defence chemicals that C. brunneum does not have and this explains why C. giveni has become a serious pest of pasture throughout New Zealand (Lefort et al. 2015a,b). Further relating to the Wiseana spp. ...
Article
Full-text available
New Zealand's intensive pastures, comprised almost entirely introduced Lolium L. and Trifolium L. species, are arguably the most productive grazing-lands in the world. However, these areas are vulnerable to destructive invasive pest species. Of these, three of the most damaging pests are weevils (Coleoptera: Curculionidae) that have relatively recently been controlled by three different introduced parasitoids, all belonging to the genus Microctonus Wesmael (Hymenoptera: Braconidae). Arguably that these introduced parasitoids have been highly effective is probably because they, like many of the exotic pest species, have benefited from enemy release. Parasitism has been so intense that, very unusually, one of the weevils has now evolved resistance to its parthenogenetic parasitoid. This review argues that New Zealand's high exotic pasture pest burden is attributable to a lack of pasture plant and natural enemy diversity that presents little biotic resistance to invasive species. There is a native natural enemy fauna in New Zealand that has evolved over millions of years of geographical isolation. However, these species remain in their indigenous ecosystems and, therefore, play a minimal role in creating biotic resistance in the country's exotic ecosystems. For clear ecological reasons relating to the nature of New Zealand pastures, importation biological control can work extremely well. Conversely, conservation biological control is less likely to be effective than elsewhere.
... In New Zealand, the introduction of exotic pastoral plants has resulted in alteration of the 63 diet of the native coleopteran Costelytra zealandica (White) (Scarabaeidae), resulting in 64 the larvae of this endemic insect to feed intensively on the roots of ryegrass and white 65 clover and being ranked as a major economic pest (Pottinger, 1975;Richards et al., 66 1997). Interestingly and in contrast, C. brunneum (Broun), a close congeneric species, is 67 not often found in ryegrass and white clover pastures and remains mostly distributed in 68 native habitats (Given, 1966;Lefort et al., 2012Lefort et al., , 2013 (Stewart 1972, Kain 1975). These two species are sympatric and 73 share similar native hosts, mainly comprising tussock species (Poaceae) commonly found 74 in New Zealand native grasslands (Given, 1966;Lefort et al., 2012Lefort et al., , 2013. ...
... Interestingly and in contrast, C. brunneum (Broun), a close congeneric species, is 67 not often found in ryegrass and white clover pastures and remains mostly distributed in 68 native habitats (Given, 1966;Lefort et al., 2012Lefort et al., , 2013 (Stewart 1972, Kain 1975). These two species are sympatric and 73 share similar native hosts, mainly comprising tussock species (Poaceae) commonly found 74 in New Zealand native grasslands (Given, 1966;Lefort et al., 2012Lefort et al., , 2013. 75 ...
Article
Full-text available
Widespread replacement of native ecosystems by productive land sometimes results in the outbreak of a native species. In New Zealand, the introduction of exotic pastoral plants has resulted in the diet alteration of the native coleopteran species, Costelytra zealandica (White) (Scarabaeidae) such that this insect has reached the status of pest. In contrast, C. brunneum (Broun), a close congeneric species, has not developed such a relationship with these ‘new’ host plants. This study investigated the feeding preferences and fitness performance of these two closely related scarab beetles to increase fundamental knowledge about the mechanisms responsible for the development of invasive characteristics in native insects. To this end the feeding preferences of larvae of both Costelytra species were investigated under controlled conditions and the survival and larval growth of the invasive species C. zealandica were compared on native and exotic host plants. Costelytra zealandica, when sampled from exotic pastures, was unable to fully utilise its ancestral native host and showed better performance on exotic plants. In contrast, C. zealandica sampled from native grasslands did not perform significantly better on either host and showed similar feeding preferences to C. brunneum. This study suggests the possibility of strong intra-specific variation, in the ability of C. zealandica to exploit native or exotic plants, supporting the hypothesis that such ability underpins the existence of distinct host-races in this species.
... In New Zealand, the introduction of exotic pastoral plants has resulted in alteration of the 63 diet of the native coleopteran Costelytra zealandica (White) (Scarabaeidae), resulting in 64 the larvae of this endemic insect to feed intensively on the roots of ryegrass and white 65 clover and being ranked as a major economic pest (Pottinger, 1975;Richards et al., 66 1997). Interestingly and in contrast, C. brunneum (Broun), a close congeneric species, is 67 not often found in ryegrass and white clover pastures and remains mostly distributed in 68 native habitats (Given, 1966;Lefort et al., 2012Lefort et al., , 2013 (Stewart 1972, Kain 1975). These two species are sympatric and 73 share similar native hosts, mainly comprising tussock species (Poaceae) commonly found 74 in New Zealand native grasslands (Given, 1966;Lefort et al., 2012Lefort et al., , 2013. ...
... Interestingly and in contrast, C. brunneum (Broun), a close congeneric species, is 67 not often found in ryegrass and white clover pastures and remains mostly distributed in 68 native habitats (Given, 1966;Lefort et al., 2012Lefort et al., , 2013 (Stewart 1972, Kain 1975). These two species are sympatric and 73 share similar native hosts, mainly comprising tussock species (Poaceae) commonly found 74 in New Zealand native grasslands (Given, 1966;Lefort et al., 2012Lefort et al., , 2013. 75 ...
Article
Full-text available
Widespread replacement of native ecosystems by productive land sometimes results in the outbreak of a native species. In New Zealand, the introduction of exotic pastoral plants has resulted in the diet alteration of the native coleopteran species, Costelytra zealandica (White) (Scarabaeidae) such that this insect has reached the status of pest. In contrast, C. brunneum (Broun), a close congeneric species, has not developed such a relationship with these ‘new’ host plants. This study investigated the feeding preferences and fitness performance of these two closely related scarab beetles to increase fundamental knowledge about the mechanisms responsible for the development of invasive characteristics in native insects. To this end the feeding preferences of larvae of both Costelytra species were investigated under controlled conditions and the survival and larval growth of the invasive species C. zealandica were compared on native and exotic host plants. Costelytra zealandica, when sampled from exotic pastures, was unable to fully utilise its ancestral native host and showed better performance on exotic plants. In contrast, C. zealandica sampled from native grasslands did not perform significantly better on either host and showed similar feeding preferences to C. brunneum. This study suggests the possibility of strong intra-specific variation, in the ability of C. zealandica to exploit native or exotic plants, supporting the hypothesis that such ability underpins the existence of distinct host-races in this species.
... Our result, however, validates the ability of COI to assign white grub species to their respective conspecifics adults. Similar results have been also found over scarab beetles by a number of previous studies (Ahrens et al. 2007;Dittrich-Schroder et al. 2009;S ıpek & Dirk 2011;Lefort et al. 2011Lefort et al. , 2013. In our case, failures only occurred when no adults were collected or poorly conserved for a given specific species. ...
Article
Full-text available
White grubs are key vegetables soil pests in Rwanda. However, aforementioned insect pests are unknown. We monitored adults with light traps and excavated larvae during cropping seasons of 2014 and 2015. Totally, 42 species were collected. The peak flights of key insect pests occurred from August to October and mid-March. The cytochrome C oxidase I (COI) gene was amplified with polymerase chain reaction (PCR) and used to compare larval DNA against DNA from adults by using MEGA 6, GMYC and ABGD software. The results obtained validate the use of COI gene. The identification results will help to predict critical time for management practices.
... An opportunity to test this is presented here by a comparison of the invasive scarab Costelytra zealandica (White) (Scarabaeidae: Melolonthinae) with the closely related non-invasive species C. brunneum. These insects are endemic to New Zealand and also occur sympatrically in several places (Given, 1966; Lefort et al., 2012; Lefort et al., 2013). The extended geographical occurrence of C. zealandica, and its severe negative impact on agro-ecosystems, suggests that it has reached a high degree of invasiveness within its home range. ...
Article
Full-text available
In the field of invasion ecology, the determination of a species' environmental tolerance, is a key parameter in the prediction of its potential distribution, particularly in the context of global warming. In poikilothermic species such as insects, temperature is often considered the most important abiotic factor that affects numerous life-history and fitness traits through its effect on metabolic rate. Therefore the response of an insect to challenging temperatures may provide key information as to its climatic and therefore spatial distribution. Variation in the phosphoglucose-6-isomerase (PGI) metabolic enzyme-system has been proposed in some insects to underlie their relative fitness, and is recognised as a key enzyme in their thermal adaptation. However, in this context it has not been considered as a potential mechanism contributing to a species invasive cability. The present study aimed to compare the thermal tolerance of an invasive scarabaeid beetle, Costelytra zealandica (White) with that of the closely related, and in part sympatrically occurring, congeneric non-invasive species C. brunneum (Broun), and to consider whether any correlation with particular PGI genotypes was apparent. Third instar larvae of each species were exposed to one of three different temperatures (10, 15 and 20 • C) over six weeks and their fitness (survival and growth rate) measured and PGI phenotyping performed via cellulose acetate electrophoresis. No consistent relationship between PGI genotypes and fitness was detected, suggesting that PGI may not be contributing to the invasion success and pest status of C. zealandica.
... An experiment was carried out where larval populations of C. zealandica and its congener, the non-pest C. brunneum, were fed with the roots of white clover, in which defence compounds were artificially triggered by the phytohormone JA.) were used for this experiment. Larvae were identified to species level on the basis of their raster morphology (Lefort et al. 2013), and for a few difficult specimens, a rapid diagnostic confirmation was performed using the DNA recovered from their frass (Lefort et al. 2012). White clover plants were grown from seeds in 200 ml of sowing mix comprising 60% peat and 40% sterilised pumice stones. ...
Article
Full-text available
Occasionally, exotic plant introductions lead to the emergence of an invasive insect within its native geographical range. Such emergence could be explained by a pre-adaptation of the insect to break through the defences of the new encountered host. We investigated the fitness responses of two New Zealand endemic scarabs (Costelytra brunneum and C. zealandica) when given a diet of an exotic pasture species, Trifolium repens, whose defences were artificially triggered by the phytohormone jasmonic acid. We found differential fitness responses between the two species when they were exposed to a defence-induced diet. We observed a significant weight increase in the invasive species C. zealandica when it was fed with treated roots compared with untreated controls, whereas no significant weight increase was observed in the non-invasive C. brunneum compared with the control treatments. Our study suggests that C. zealandica has a pre-existing ability to tolerate the defence chemicals of its exotic host and, more interestingly, to benefit from them, which may explain why this species has become a serious pest of pasture throughout its native geographical range.
Preprint
Full-text available
In the field of invasion ecology, the determination of a species environmental tolerance, is a key parameter in the prediction of its potential distribution, particularly in the context of global warming. In poikilothermic species such as insects, temperature is often considered the most important abiotic factor that affects numerous life-history and fitness traits through its effect on metabolic rate. Therefore the response of an insect to challenging temperatures may provide key information as to its climatic and therefore spatial distribution. Variation in the phosphoglucose-6-isomerase (PGI) metabolic enzyme-system has been proposed in some insects to underlie their relative fitness, and is recognised as a key enzyme in their thermal adaptation. However, in this context it has not been considered as a potential mechanism contributing to a species invasive cability. The present study aimed to compare the thermal tolerance of an invasive scarab, Costelytra zealandica (White) with that of the closely related, and in part sympatrically occurring, congeneric non-invasive species C. brunneum (Broun), and to consider whether any correlation with particular PGI phenotypes was apparent. Third instar larvae of each species were exposed to one of three different temperatures (10, 15 and 20°C) over six weeks and their fitness (survival and growth rate) measured and PGI phenotyping performed via cellulose acetate electrophoresis. No relationship between PGI phenotypes and fitness was detected, suggesting that the PGI may not be contributing to the invasion success and pest status of C. zealandica .
Article
Diloboderus abderus (Sturm, 1826) (Coleoptera: Melolonthidae) is a serious soil pest of corn, wheat, oat, and natural and cultivated pastures in Argentina, Paraguay, Uruguay, and southern Brazil. Despite its economic importance, the genetic diversity and population structure of D. abderus remain unknown. We sequenced a fragment of the mitochondrial gene cytochrome oxidase I region (COI), of six populations of D. abderus from the Southern Cone of America. The mtDNA marker revealed a high haplotype diversity, high pairwise FST values, and significant genetic variations among populations. No correlation was found between genetic and geographical distances, yet the most common haplotype (Dab01) was present in four out of the six populations. Analysis of molecular variance showed that most of the variation was within populations of D. abderus. Tajima’s D and Fu’s FS tests indicated no evidence that D. abderus populations are under recent expansion. Our results indicate that genetic-based traits will likely remain localized or spread slowly, and management strategies need to be undertaken on a small scale.
Article
Full-text available
Widespread replacement of native ecosystems by productive land sometimes results in the outbreak of a native species. In New Zealand, the introduction of exotic pastoral plants has resulted in diet alteration of the native coleopteran species, Costelytra zealandica (White) (Scarabaeidae) such that this insect has reached the status of pest. In contrast, C. brunneum (Broun), a congeneric species, has not developed such a relationship with these ‘novel’ host plants. This study investigated the feeding preferences and fitness performance of these two closely related scarab beetles to increase fundamental knowledge about the mechanisms responsible for the development of invasive characteristics in native insects. To this end, the feeding preference of third instar larvae of both Costelytra species was investigated using an olfactometer device, and the survival and larval growth of the invasive species C. zealandica were compared on native and exotic host plants. Costelytra zealandica , when sampled from exotic pastures, was unable to fully utilise its ancestral native host and showed higher feeding preference and performance on exotic plants. In contrast, C. zealandica sampled from native grasslands did not perform significantly better on either host and showed similar feeding preferences to C. brunneum , which exhibited no feeding preference. This study suggests the possibility of strong intraspecific variation in the ability of C. zealandica to exploit native or exotic plants, supporting the hypothesis that such ability underpins the existence of distinct host-races in this species.
Article
Full-text available
Only recently has it been formally acknowledged that native species can occasionally reach the status of 'pest' or 'invasive species' within their own native range. The study of such species has potential to help unravel fundamental aspects of biological invasions. A good model for such a study is the New Zealand native scarab beetle, Costelytra zealandica (White), which even in the presence of its natural enemies has become invasive in exotic pastures throughout the country. Because C. zealandica still occurs widely within its native habitat, we hypothesised that this species has only undergone a host range expansion (ability to use equally both an ancestral and new host) onto exotic hosts rather than a host shift (loss of fitness on the ancestral host in comparison to the new host). Moreover, this host range expansion could be one of the main drivers of its invasion success. In this study, we investigated the fitness response of populations of C. zealandica from native and exotic flora, to several feeding treatments comprising its main exotic host plant as well as one of its ancestral hosts. Our results suggest that our initial hypothesis was incorrect and that C. zealandica populations occurring in exotic pastures have experienced a host-shift rather than simply a host-range expansion. This finding suggests that an exotic plant introduction can facilitate the evolution of a distinct native host-race, a phenomenon often used as evidence for speciation in phytophagous insects and which may have been instrumental to the invasion success of C. zealandica.
Article
Full-text available
Grass grub, Costelytra zealandica, is a species endemic to New Zealand and the only one of eleven described Costelytra species which has become a significant pasture pest. Specimens were collected from throughout New Zealand and the DNA subjected to the polymerase chain reaction using primers specific to a highly conserved region of ribosomal DNA. A surprising degree of genetic variation was revealed when the amplified products were sequenced and compared. Grass grub populations could be split into two geographical groups, North Island and South Island, based on the similarity of ribosomal DNA. INTRODUCTION Grass grub, Costelytra zealandica (White) (Coleoptera: Scarabaeidae: Melolonthinae), is one of the worst pasture pests in New Zealand, causing up to $89M in lost production per year (Garnham and Barlow 1993). It is one of the few native insects to become a major pest after intensification of agriculture in the last 150 years. The genus Costelytra was erected by Given (1952) and originally contained six species which were classified on the morphology of the male genital claspers. A further five species were added to the genus in subsequent reviews by Given (1960; 1966). Only two species, C. zealandica and C. brunneum (Broun), have been found in both the North and South Islands (Given 1966). C. zealandica, the only pest species, has a wide distribution throughout New Zealand, including the Chatham Islands, and is found existing from sea level to over 4000 ft, through most soil types and most plant communities (Given 1966). Despite the wide geographical spread and variations in climate, it is recorded as one species, with no obvious morphological differences observed in any regional populations (Given 1952). However, there have been anecdotal comments that 3rd instar larvae from Taranaki are, on average, larger than from other regions (Townsend pers. comm.). Many molecular biology techniques have proved useful in the study of intraspecific variation. Previously, the study of conserved ribosomal DNA (rDNA) has contributed to understanding the variation in a number of systems including insects (eg. Pfeifer et al. 1995) and fungi (eg. Curran et al. 1994). These studies used polymerase chain reaction (PCR) amplification of the variable internal transcribed spacer regions (ITS1 and/or 2) and the more conserved intervening 5.8S of the rDNA to compare strains and species. In this study we compared sequences of rDNA from the 16S/18S to the 5.8S regions encompassing all of the ITS1 region to determine the level of intraspecific variation in a small sample of C. zealandica. MATERIALS AND METHODS Collection of Specimens Grass grub larvae were field-collected from around New Zealand (Table 1). Other members of the subfamily Melolonthinae (C. brunneum, Chlorochiton suturalis, Pyronota sp. [festiva?] and Odontria sp.) and the sand scarab, Pericoptus truncatus Fabricius (Dynastinae), were included as outliers for the genetic analyses.
Article
The Sanitary and Phytosanitary Agreement of the World Trade Organisation specifies that countries cannot regulate against unknown pests, yet many alien invasive forest pests are unknown to science prior to discovery in a new land. Many of these pests are introduced via nursery stock, but lack of pest information makes this pathway difficult to mitigate. Botanic gardens and arboreta worldwide offer a unique opportunity to help detect potential invasive threats to forest health before they spread. Monitoring pests in gardens with international collections could inform prevention activities as well as help promote early detection and rapid response to new pest incursions. While recognising the inherent value of single country-pair studies currently ongoing, and the scientific integrity expected of resulting peer-reviewed publications, we believe opportunities for synergy across these efforts and for more immediate response to new host-pest associations should be explored. The strengths and weaknesses of various current approaches to sentinel plant monitoring are described, as well as a strategy for developing a worldwide network of gardens sharing information on pests that would extend the lessons learned and direct timely information to National Plant Protection Organisations to enhance protection of natural resources. © 2010 New Zealand Forest Research Institute Limited, trading as Scion.
Article
The third instar larvae of three Anisoplia species, Anisoplia baetica Erichson, 1847, Anisoplia depressa Erichson, 1847 and Anisoplia remota Reitter, 1889 are described and illustrated to show the diagnostic characters of the species. The third instar larva of the monospecific genus Anthoplia, represented by Anthoplia floricola (F., 1787) is also described and illustrated. These four species are included in a revised key to the larvae of Anisopliini, which now includes four genera, and ten species. The taxonomic status of Anthoplia based on the larval morphology, is discussed.
Article
In attempting to understand the distributions of both introduced species and the native species on which they impact, there is a growing trend to integrate studies of behaviour with more traditional life history/ecological approaches. The question of what mechanisms drive the displacement of the freshwater amphipod Gammarus duebeni by the often introduced G. pulex is presented as a case study. Patterns of displacement are well documented throughout Europe, but the speed and direction of displacement between these species can be varied. From early studies proposing interspecific competition as causal in these patterns, I review research progress to date. I show there has been no evidence for interspecific competition operating, other than the field patterns themselves, a somewhat tautological argument. Rather, the increased recognition of behavioural attributes with respect to the cannibalistic and predatory nature of these species gave rise to a series of studies unravelling the processes driving field patterns. Both species engage in ‘intraguild predation’ (IGP), with moulting females particularly vulnerable to predation by congeneric males. G. pulex is more able both to engage in and avoid this interaction with G. duebeni. However, several factors mediate the strength and asymmetry of this IGP, some biotic (e.g. parasitism) and others abiotic (e.g. water chemistry). Further, a number of alternative hypotheses that may account for the displacement (hybridization; parasite transmission) have been tested and rejected. While interspecific competition has been modelled mathematically and found to be a weak interaction relative to IGP, mechanisms of competition between these Gammarus species remain largely untested empirically. Since IGP may be finely balanced in some circumstances, I conclude that the challenge to detect interspecific competition remains and we require assessment of its role, if any, in the interaction between these species. Appreciation of behavioural attributes and their mediation should allow us to more fully understand, and perhaps predict, species introductions and resultant distributions.
Article
Larvae of the New Zealand grass grub (Costelytra zealandica) were treated with the entomopathogenic fungus, Metarhizium anisopliae, and the bacterium, Serratia entomophila, singly and in combination. The mortality of second instar larvae up to 41 days in treatments with both pathogens together was significantly greater than the additive mortalities of single pathogen treatments, and therefore synergistic. Treatment of third instar larvae with both pathogens did not increase mortality compared with the fungus alone. Second instar larvae were more resistant to M. anisopliae than third instar larvae. S. entomophila causes a chronic disease and bacterial treatments alone resulted in disease, but little mortality for either instar within 5 weeks. In both fungus alone and fungus/bacteria treatments, less than half the cadavers supported fungal sporulation. The use of a dual pathogen system for control of grass grub larvae is discussed.
Article
Descriptions are provided for the final-instar larvae of the following species of Scarabaeidae, which live and feed in the root zone of pastures in Tasmania. Dynastinae: Cheiroplatys latipes (Guerin-Meneville), Pimelopus nothus Burmeister and Adoryphorus couloni (Burmeister). Rutelinae: Saulostomus villosus Waterhouse and Anoplognathus suturalis Boisduval. Melolonthinae: Phyllotocus macleayi Fischer, P. bimaculatus Erichson, P. nigripennis Lea, P. rufipennis (Boisduval), Automolus depressus (Blanchard), Colpochila obesa Boisduval, Liparetrus sp., Telura sp., T. vitticollis Erichson, Scitala sericans Erichson, Sericesthis nigra (Lea), S. nigrolineata (Boisduval), Diphucephala colaspidoides (Gyllenhal), D. smaragdula Boisduval and Heteronyx tasmanicus Blackburn. Keys are also provided which enable the species to be distinguished from each other by means of features generally visible at low magni- fication.
Article
Over the past two years a number of field studies of protozoan diseases in Costelytra zealandica (White) have been undertaken. Information has been gained on the distribution of these diseases in New Zealand, the incidence of infection in the life cycle and in populations of grass grub transmission of the organisms, and the effects of each protozoan species on growth, development, and mortality of grass grub. The results of these preliminary investigations are discussed.
Article
A crude extract of lucerne root (Medicago sativa ’Wairau') was found to contain a strong feeding deterrent for 3rd‐instar Costelytra zealandica (White) larvae when tested at fresh‐root concentration. Purified saponins obtained from such an extract by standard procedures markedly reduced feeding, and had an ED50 of 0.019%. A commercial preparation of naturally derived saponins was also an effective feeding deterrent, with an ED50 of 0.18%. Considerable variation was found in the saponin levels present in the root of 13 cultivars of lucerne. A role for saponins in the resistance of lucerne to grass grub attack seems probable, but the mechanism of that role remains uncertain.
Article
Based on a comparative molecular study of scarab chafers we matched adult and larval instars to identify and describe unknown larvae of Sericini. Here, we use for the first time a two-fold DNA taxonomy approach based on: (i) mitochondrial and nuclear DNA markers of a local sample (from Nepal) of adults and larvae, in combination with character and tree-based species delimitation methods; and (ii) a global search of cytochrome c oxidase subunit I (cox1) sequences with GenBank data. In the latter analysis we used a sequence of a specimen that resulted in the first analysis conspecific with the larvae of Maladera affinis (Blanchard) as the query sequence in GenBank, and checked in a minimum evolution tree whether larva–adult matches from the local approach were altered through interference with other taxa of the worldwide database. Both approaches unambiguously identified the unknown larvae as belonging to M. affinis and Maladera cardoni (Brenske). Based on this robust framework of taxonomic identification we could associate names to the larval morphology of the third larval instar of these two Nepalese Maladera species, which are both known for their economical importance in agriculture. They are described here in detail and are compared with known related taxa, especially with Maladera castanea (Arrow).