Aquatic Macrophyte Vegetation Promotes Taxonomic and Functional Diversity of Odonata Assemblages in Intermittent Karst Rivers in the Mediterranean

Assemblages of adult Odonata were studied in four intermittent karst rivers encompassing macrophyte-rich (MRH) and macrophyte-poor habitats (MPH) in southern Europe, where temporary lotic habitats are the predominant freshwater type but are still understudied. With a total of 25 recorded species, the studied habitats support species-rich Odonata assemblages, as already shown for intermittent rivers in the Mediterranean. Aquatic macrophyte abundance, conductivity, and water velocity are the most significant determinants of Odonata assemblages in the studied IRES. MRH promote higher Odonata abundance and the taxonomic and functional diversity of their assemblages compared to the MPH. Odonata assemblages in MRH are characterized by higher values of body size and a higher share of species preferring lentic and temporary hydrological conditions. Moreover, their assemblages are characterized by various patterns of nymphal development and drought resilience strategies. In contrast, MPH are preferred by lotic species, with nymphal development all year round and with no specific drought-resisting strategies. Our results contribute to the knowledge of diversity and ecological requirements of dragonflies and damselflies in IRES habitats, which could provide scientific background for future conservation activities and bioassessment protocols of such habitats and their biota.

The boom and bust of the aphid’s essential amino acid metabolism across nymphal development

Within long term symbioses animals integrate their physiology and development with their symbiont. In a model nutritional mutualism, aphids harbor the endosymbiont, Buchnera, within specialized bacteriocyte cells. Buchnera synthesizes essential amino acids (EAA) and vitamins for their host, which are lacking from the aphid’s plant sap diet. It is unclear if the aphid host differentially expresses aphid EAA metabolism pathways and genes that collaborate with Buchnera for the production of EAA and vitamins throughout nymphal development when feeding on plants. It is also unclear if aphid bacteriocytes are differentially methylated throughout aphid development as DNA methylation may play a role in gene regulation. By analyzing aphid gene expression, we determined that the bacteriocyte is metabolically more active in metabolizing Buchnera’s EAAs and vitamins early in nymphal development compared to intermediate or later immature and adult lifestages. The largest changes in aphid bacteriocyte gene expression, especially for aphid genes that collaborate with Buchnera, occurred during the 3rd to 4th instar transition. During this transition there is a huge shift in the bacteriocyte from a high energy ‘nutrient-consuming state’ to a ‘recovery and growth state’ where patterning and signaling genes and pathways are upregulated and differentially methylated, and de novo methylation is reduced as evidenced by homogenous DNA methylation profiles after the 2nd instar. Moreover, bacteriocyte number increased and Buchnera’s titer decreased throughout aphid nymphal development. These data suggest in combination that bacteriocytes of older nymphal and adult lifestages depend less on the nutritional symbiosis compared to early nymphal lifestages.

Morphology, development and reproduction of Atractomorpha acutipennis (Guérin-Méneville, 1844) (Orthoptera: Pyrgomorphidae)

For a better knowledge of Atractomorpha acutipennis bio-ecology and to facilitate its identification, we studied the morphology, development and reproduction of this grasshopper on Manihot esculenta under laboratory conditions. Five hundred and fifty-one first nymphal stages obtained in the laboratory were reared in cages. Some body parts allowed a clear identification of different nymphal instars. Post-embryonic development passed through six stages (males) and seven stages (females). Mean nymphal development time was 17.14 ± 0.62, 12.91 ± 0.62, 13.45 ± 0.69, 13.80 ± 0.68, 15.23 ± 0.55 days respectively in males nymphal instars 1 to 5 and 16.18 ± 0.54, 13.13 ± 0.59, 12.49 ± 0.42, 13.19 ± 0.58, 14.58 ± 0.61, 16.57 ± 0.68 days respectively, in females nymphal instars 1 to 6. Adult females deposited an average of 3.67 ± 2 egg pods each comprising 30.77 ± 10.5 eggs. First mating was observed 18 ± 15.42 days after the last moult. Oviposition occured on average 19.33± 5.33 days after the first mating. This study provides important information about the biology of A. acutipennis, which could help in developing control methods against this grasshopper in southern Cameroon.

Populations and Host/Non-Host Plants of Spittlebugs Nymphs in Olive Orchards from Northeastern Portugal

The Aphrophoridae family contains important vectors of Xylella fastidiosa, a serious bacterial plant disease. In olive orchards, nymphs usually feed on the ground-cover vegetation. However, detailed information about their populations and host/non-host plants in some regions threatened by Xylella, such as the northeast of Portugal, is very limited. The goal of our work was to identify the vector species, nymphal development period, and their host and non-host herbaceous plants in olive orchards from northeastern Portugal. Ground-cover plant species hosting or not hosting nymphs were identified during the spring of 2017 to 2019 in olive orchards. Nymphal development period, nymph aggregation, and nymph’s preferred feeding height of the ground-cover plants were recorded. The most abundant Aphrophoridae species was Philaenus spumarius followed by Neophilaenus sp. Nymphs developed from April to early May and showed a low number of individuals per foam (generally between one and three). They preferred the middle part of the plants. Philaenus spumarius feeds preferentially on Asteraceae and Fabaceae, and Neophilaenus sp. on Poaceae. Some abundant plants, such as Bromus diandrus, Astragalus pelecinus, Chrysanthemum segetum, Trifolium spp., Caryophyllaceae, and Brassicaceae, were barely colonized by Aphrophoridae nymphs. This knowledge is essential for the selection of the species composition of ground-cover vegetation to minimize the presence of vectors of X. fastidiosa in olive groves.

PARAMETER KEHIDUPAN DAN DEMOGRAFI KEPIK, Diconocoris hewetti (Dist.) (HEMIPTERA: TINGIDAE) PADA DUA VARIETAS LADA

ABSTRAK<br />Kepik renda lada (KRL), Diconocoris hewetti (Dist.) (Hemiptera:<br />Tingidae) adalah salah satu hama pada pertanaman lada di Indonesia.<br />Penelitian bertujuan untuk membandingkan berbagai parameter kehidupan<br />dan demografi KRL pada dua varietas lada. Pengaruh varietas lada<br />terhadap parameter kehidupan dan demografi KRL diteliti di rumah kasa<br />dan pertanaman lada di Pulau Bangka, sejak Oktober 2003 hingga Februari<br />2004. Penelitian mencakup pengaruh varietas Chunuk dan LDL terhadap<br />masa perkembangan telur dan nimfa, lama hidup imago jantan dan betina,<br />serta keperidian. Selain itu juga diteliti pengaruh fase bunga, pucuk daun,<br />dan buah muda terhadap lama hidup imago. Pengaruh varietas terhadap<br />berbagai parameter demografi KRL dipelajari dengan memelihara kepik<br />dari sejak telur hingga imago yang muncul meletakkan telur kembali.<br />Hasil penelitian menunjukkan bahwa perbedaan varietas mempengaruhi<br />berbagai parameter kehidupan KRL. Lama perkembangan nimfa 17,3 dan<br />13,0 hari, lama hidup imago jantan 10,2 dan 18,8 hari, lama hidup imago<br />betina 13,6 dan 16,9 hari, keperidian 13,9 dan 24,5 butir, berturut-turut<br />pada varietas Chunuk dan LDL. Imago KRL hidup lebih lama pada bunga<br />fase-3 dibandingkan pada bunga fase-1 atau-2. Laju pertambahan intrinsik<br />(r) 0,0741 dan 0,0827; laju reproduksi bersih (Ro) 6,98 dan 8,52, masa<br />generasi (T) 26,21 dan 25,91; laju pertambahan terbatas (λ) 1,0769 dan<br />1,0862 berturut-turut pada varietas Chunuk dan LDL. Secara keseluruhan,<br />varietas LDL lebih mendukung kehidupan dan perkembangan populasi D.<br />hewetti. Jika tidak tersedia bunga lada KRL mampu bertahan hidup dengan<br />mengisap pucuk daun dan buah muda. Lama hidup imago 12,1 hari dan<br />23,5 hari pada buah muda. Implikasi dari hasil penelitian ini adalah<br />informasi dasar dalam penelitian untuk pengendalian KRL.<br />Kata kunci: Lada, Piper nigrum L., hama, kepik renda lada, Diconocoris<br />hewetti, parameter kehidupan, demografi, Propinsi Bangka<br />Belitung<br />ABSTRACT<br />Life parameters and demographic of bug peper lace<br />Diconocoris hewetti (Dist.) (Hemiptera: Tingidae) on two<br />pepper varieties<br />Pepper lace bug (PLB), Diconocoris hewetti (Dist.) (Hemiptera:<br />Tingidae), is one of the insect pests attacking pepper in Indonesia.<br />Research was conducted with the objective to compare various life history<br />and demographic parameters of PLB on two pepper varieties. The effect<br />of two pepper varieties on various life parameters and demographic of<br />PLB was conducted in green house and farmer field on Bangka Island,<br />since October 2003 to February 2004. The experiment covered the effect<br />of LDL and Chunuk varieties on eggs and nymphal development, male<br />and female adults longivity and fecundity. Besides the effect of<br />development stage on inflorescence, shoots and young berries to adults<br />longivity were observed. The effect of varieties to demographic parameters<br />of PLB was studied by rearing the bugs since egg to adult laid eggs. The<br />result revealed that difference variety was influenced life history and<br />demographic parameters of PLB. Nymphal development time of PLB were<br />17.3 and 13.0 days, male adult longivity 10.2 and 18.8 days, female adult<br />longivity 13.6 and 16.9 days, fecundity 13.9 and 24.5 eggs per female,<br />respectively on Chunuk and LDL. The life history of PLB adult was longer<br />on stage-3 inflorescences than stage-1 or stage-2. The intrinsic rates of<br />increase (r) were 0.0741 and 0.0827, net reproductive rate (Ro) 6.98 and<br />8.52, mean generation time (T) 26.21 and 25.91 days, finite rate of<br />increase (λ) 1.0769 and 1.0862 on Chunuk and LDL<br />respectively.Generally, variety LDL was much better food source for the<br />development of D. hewetti. If there were no inflorescences available, the<br />PLB was able to survive by feeding on shoots or young berries. Adult<br />longivity was 12.1 days on shoots and 23.5 days on young berries. The<br />implication of this research is as the basic information in the next research<br />for PLB control.<br />Key words : Pepper, Piper nigrum L., pest, lace bug, Diconocoris hewetti,<br />life parameters, demographic, Bangka Belitung Province

Photoperiod and temperature separately regulate nymphal development through JH and insulin/TOR signaling pathways in an insect

Insects living in the temperate zone enter a physiological state of arrested or slowed development to overcome an adverse season, such as winter. Developmental arrest, called diapause, occurs at a species-specific developmental stage, and embryonic and pupal diapauses have been extensively studied in mostly holometabolous insects. Some other insects overwinter in the nymphal stage with slow growth for which the mechanism is poorly understood. Here, we show that this nymphal period of slow growth is regulated by temperature and photoperiod through separate pathways in the cricket Modicogryllus siamensis. The former regulates the growth rate, at least in part, through the insulin / target of rapamycin (TOR) signaling pathway. Lower temperature down-regulates the expression of insulin-like peptide (Ms’Ilp) and Target of rapamycin (Ms’Tor) genes to slow down the growth rate without affecting the number of molts. The latter regulates the number of molts independent of temperature. Short days increase the number of molts through activation of the juvenile hormone (JH) pathway and down-regulation of myoglianin (Ms’myo), a member of the TGFβ family, which induces adult metamorphosis. In contrast, long days regulate Ms’myo expression to increase during the fifth to sixth instar to initiate adult metamorphosis. When Ms’myo expression is suppressed, juvenile hormone O-methyl transferase (Ms’jhamt) was up-regulated and increased molts to prolong the nymphal period even under long-day conditions. The present findings suggested that the photoperiod regulated Ms’myo, and the JH signaling pathway and the temperature-controlled insulin/TOR pathway cooperated to regulate nymphal development for overwintering to achieve seasonal adaptation of the life cycle in M. siamensis.