Microhabitat Variation in Egg Diapause Incidence in Summer Within a Local Population: An Adaptation to Decline in Host-Plant Suitability in Trigonotylus caelestialium (Hemiptera: Miridae)

2020 ◽  
Vol 49 (4) ◽  
pp. 912-917
Author(s):  
Yoshinori Shintani ◽  
Keisuke Nagamine

Abstract Diapause induction in multivoltine insects is an ecophysiological event that is generally triggered by seasonal cues such as photoperiod and temperature. The rice leaf bug, Trigonotylus caelestialium (Kirkaldy), feeds on various Poaceae grasses and produces several generations a year. Previous studies have shown that adults produce diapause and nondiapause eggs under short-day and long-day conditions, respectively. However, there is a distinct mid-summer peak in diapause incidence before an autumnal increase in diapause incidence in the field, which cannot be explained by the laboratory results. The present study was performed to examine the environmental factors affecting the diapause incidence in mid-summer and the adaptive significance of this phenomenon. Seasonal trends in diapause incidence differed significantly among three sites located 150–400 m apart from each other and with different host plants. The suitability of host plants differs depending on species and seasonally. Therefore, the microhabitat difference in diapause trend is believed to be due to the difference in host plants. When field-collected female adults laying diapause eggs in late June were fed a seasonally deteriorating host (the orange foxtail, Alopecurus aequalis Sobol. [Poales: Poaceae]), they kept laying diapause eggs, whereas when fed a suitable host (the wheat, Triticum aestivum L. [Poales: Poaceae]) for 5 d, they changed oviposition mode to lay nondiapause eggs. These results indicate that host-plant suitability affects the oviposition mode of T. caelestialium. Diapause-egg oviposition in mid-summer in T. caelestialium has adaptive significance as a bet-hedging strategy against unpredictable dietary conditions.

Author(s):  
Marcin W. Zielonka ◽  
Tom W. Pope ◽  
Simon R. Leather

Abstract The carnation tortrix moth, Cacoecimorpha pronubana (Hübner, [1799]) (Lepidoptera: Tortricidae), is one of the most economically important insect species affecting the horticultural industry in the UK. The larvae consume foliage, flowers or fruits, and/or rolls leaves together with silken threads, negatively affecting the growth and/or aesthetics of the crop. In order to understand the polyphagous behaviour of this species within an ornamental crop habitat, we hypothesized that different host plant species affect its life history traits differently. This study investigated the effects of the host plant species on larval and pupal durations and sizes, and fecundity (the number of eggs and the number and size of egg clutches). At 20°C, 60% RH and a 16L:8D photoperiod larvae developed 10, 14, 20 and 36 days faster when reared on Christmas berry, Photinia (Rosaceae), than on cherry laurel, Prunus laurocerasus (Rosaceae), New Zealand broadleaf, Griselinia littoralis (Griseliniaceae), Mexican orange, Choisya ternata (Rutaceae), and firethorn, Pyracantha angustifolia (Rosaceae), respectively. Female pupae were 23.8 mg heavier than male pupae, and pupal weight was significantly correlated with the duration of larval development. The lowest and the highest mean numbers of eggs were produced by females reared on Pyracantha (41) and Photinia (202), respectively. Clutch size differed significantly among moths reared on different host plants, although the total number of eggs did not differ. This study showed that different ornamental host plants affect the development of C. pronubana differently. Improved understanding of the influence of host plant on the moth's life history parameters measured here will help in determining the economic impact that this species may have within the ornamental plant production environment, and may be used in developing more accurate crop protection methodologies within integrated pest management of this insect.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Belén Cotes ◽  
Gunda Thöming ◽  
Carol V. Amaya-Gómez ◽  
Ondřej Novák ◽  
Christian Nansen

AbstractRoot-associated entomopathogenic fungi (R-AEF) indirectly influence herbivorous insect performance. However, host plant-R-AEF interactions and R-AEF as biological control agents have been studied independently and without much attention to the potential synergy between these functional traits. In this study, we evaluated behavioral responses of cabbage root flies [Delia radicum L. (Diptera: Anthomyiidae)] to a host plant (white cabbage cabbage Brassica oleracea var. capitata f. alba cv. Castello L.) with and without the R-AEF Metarhizium brunneum (Petch). We performed experiments on leaf reflectance, phytohormonal composition and host plant location behavior (behavioral processes that contribute to locating and selecting an adequate host plant in the environment). Compared to control host plants, R-AEF inoculation caused, on one hand, a decrease in reflectance of host plant leaves in the near-infrared portion of the radiometric spectrum and, on the other, an increase in the production of jasmonic, (+)-7-iso-jasmonoyl-l-isoleucine and salicylic acid in certain parts of the host plant. Under both greenhouse and field settings, landing and oviposition by cabbage root fly females were positively affected by R-AEF inoculation of host plants. The fungal-induced change in leaf reflectance may have altered visual cues used by the cabbage root flies in their host plant selection. This is the first study providing evidence for the hypothesis that R-AEF manipulate the suitability of their host plant to attract herbivorous insects.


Much of the information which can be obtained about a plant virus agent is ultimately derived from the quantity as well as the type of the infections resulting from inoculations to suitable host plants. The number ofinfections obtained does not depend solely on the nature of the particular virus concerned. It is dependent on other variable factors, such as the efficiency of the means of infection introducing the virus, the susceptibility of the plants receiving it, and the concentration of the virus in the source from which it was obtained. In this paper a'n attempt has been made to estimate the effect of some of these variables on infection by insects.


Nematology ◽  
2004 ◽  
Vol 6 (3) ◽  
pp. 375-387 ◽  
Author(s):  
N. Aileen Ryan ◽  
Peter Jones

AbstractSeventy bacteria, isolated from the rhizosphere of the potato cyst nematode (PCN) host plant, potato, were cultured in the presence and absence of potato root leachate (PRL) and the resultant culture filtrates were analysed for their ability to affect the hatch in vitro of the two PCN species. Of the isolates tested, nine had a significant effect on PCN hatch. Six affected Globodera pallida hatch and three affected G. rostochiensis hatch. Five of the isolates significantly increased hatch only when cultured in the presence of PRL. Three of the isolates decreased PCN hatch significantly in PRL. Only one isolate increased hatch significantly in the absence of PRL. No isolate affected the hatch of both species. Six of the nine isolates that significantly affected PCN hatch had been pre-selected by culturing on PRL. Bacterial isolates from PCN non-hosts (14 from wheat, 17 from sugar beet) were also tested for hatching activity. The principal effect of the hatch-active isolates from the PCN non-host plants was to increase PCN hatch in the presence of PRL. In contrast to the host bacteria results, the isolates from non-host plants affected only G. rostochiensis hatch (three wheat isolates and four sugar beet isolates significantly increased G. rostochiensis hatch); no such isolate affected G. pallida hatch significantly in the presence of PRL. Ten isolates (32%) from non-host plants had the ability to increase significantly the hatch of PCN in the absence of PRL (eight of these affected G. rostochiensis hatch and four affected G. pallida hatch), compared to only one bacterial isolate (1%) from a host plant. The majority of the isolates from non-hosts produced PCN species-specific effects, as with the bacteria isolated from potatoes, although two wheat isolates increased the hatch of both species significantly in the absence of PRL. Of 20 hatch-active bacterial isolates (from all three plants) identified, 70% were Bacillus spp. Other genera identified were Arthrobacter , Acinetobacter and Staphylococcus .


2000 ◽  
Vol 90 (4) ◽  
pp. 365-371 ◽  
Author(s):  
P.B. Tanzubil ◽  
G.W.K. Mensah ◽  
A.R. McCaffery

The role of the host plant in the development of larval diapause in the millet stem borer, Coniesta ignefusalis (Hampson) was investigated in northern Ghana in 1996 and 1997. Surveys conducted in farmers' fields in the Guinea and Sudan savannah revealed that of all the upland cereals grown, the insect survived the dry season only in stalks and stubble of pearl millet, Pennisetum glaucum and late sorghum, Sorghum bicolor. This observation was confirmed by results from field trials conducted at the Manga Research Station. In these studies, C. ignefusalis larvae entered diapause only in late millet and late sorghum, with a higher incidence in the former. The insect neither attacked nor entered diapause in maize planted during the same period as the other crops. Results from controlled experiments showed that diapause incidence in the preferred host, millet, was higher in older than in younger plants, suggesting that host plant maturation is a key factor influencing the development of larval diapause in C. ignefusalis.


2019 ◽  
Vol 9 (3) ◽  
pp. 151-159
Author(s):  
Magdalena Sunarti Pareira ◽  
Irdika Mansur ◽  
Dewi Wulandari

The sandalwood tree (Santalum album Linn.) is an important tree species as well as a primadonna for the people of East Nusa Tenggara (NTT). It has high economic value for its aromatic wood and essential oil content that have a very distinctive aroma used to make various products such as handicrafts, woodcarvings, incense, and oil for the perfume and cosmetics industry. Sandalwood is a semi parasite plant that part of its life phase requires a host plant to get the nutrients and water. There are many types of host plants that have been used, among others, Casuarina equisetifolia, Acacia mangium, Terminalia microcarpa, Sesbania grandiflora, Alternanthera sp and Capsicum annum. In this research will be tested to try sandalwood planted with Cymbopogon nardus host plants, in terms of economics can provide benefits.Arbuscular mycorrhizal fungi (AMF) is a group of fungi from glomeromycota phylum that can symbiosis mutualism with root system of high level plant. The working principle of the mycorrhiza is to infect the root system of the host plant, producing intensive hyphae tissue so that the plant containing mycorrhiza will be able to increase the capacity in nutrient uptake. The utilization of host plants Alternanthera sp, Capsicum annum, and its application with AMF is the best solution to overcome the problem of developing sandalwood in TTU on the nursery. The purpose of this study was to analyze the effectiveness of AMF and utilization of the atsiri host plant to increase the growth of sandalwood seedlings in TTU. This study was designed using a complete random method (RAL) in split plot design. If the treatment has a significant effect then followed by Duncan Multiple Range Test (DMRT). Parameters observed were height (cm), number of leaf, diameter of sandalwood (mm), dry weight of root, seed quality index, ratio of root buds, and haustorium observation of Sandalwood, and also number of spore, root colonization and AMF dependency of Sandalwood.The results showed that the treatment of AMF with Capsicum annum host plant was 19.8 of high, number of leaf 18.9 on FMA treatment with host plant Capsicum annum, diameter of stem 2.24 mm on Alternanthera sp host treatments without AMF and 1.83 mm at AMF treatment with host plant Capsicum annum, dry weight of buds 2.00g on AMF treatment with Capsicum annum host plant, dry weight of roots AMF (M1) with alternanthera sp 0.70 g, root buds ratio of AMF with host plant alternanthera sp 4.05, seed quality index AMF with Alternanthera sp 4.16 and 82 % of root colonization on AMF with host plant Capsicum annum.Keywords: Santalum album Linn., AMF, host plant.


2019 ◽  
Author(s):  
Yu Okamura ◽  
Ai Sato ◽  
Natsumi Tsuzuki ◽  
Masashi Murakami ◽  
Hanna Heidel-Fischer ◽  
...  

AbstractAdaptive traits that enable organisms to conquer novel niches and experience subsequent diversification are ecologically and evolutionarily important. The larvae of Pieris butterflies express nitrile-specifier proteins (NSPs), a key innovation for overcoming the glucosinolate (GLS)-myrosinase-based defense system of their Brassicales host-plants. NSPs are a member of the NSP-like gene family, which includes the major allergen (MA) protein, a paralog of NSP with a GLS-disarming function, and a single domain major allergen (SDMA) protein, whose function is unknown. The arms-race between a highly variable host-plant defense system and members of the NSP-like gene family is suggested to mediate diversification in both Pierid butterflies and Brassicales plants. Here, we combined feeding experiments using 25 Brassicaceae plants and five Pieris species with larval transcriptome data to investigate the evolutionary forces acting on NSP-like gene family members associated with patterns of host-plant usage. Although we observed significantly elevated nonsynonymous to synonymous substitution ratios in NSPs, no such pattern was observed in MAs or SDMAs. Furthermore, we found a signature of positive selection of NSP at a phylogenetic branch which reflects different host-plant preferences. Our data indicate that NSPs have evolved in response to shifting preferences for host plants among five Pieris butterflies, whereas MAs and SDMAs appear to have more conserved functions. Our results show that the evolution and functional differentiation of key genes used in host-plant adaptation play a crucial role in the chemical arms-race between Pieris butterflies and their Brassicales host-plants.


2001 ◽  
Vol 12 (3) ◽  
Author(s):  
Lauri Kaila ◽  
Bengt Bengtsson ◽  
Ivars Šulcs ◽  
Jari Junnilainen

The Elachista regificella complex (Elachistidae) is revised and considered to consist of three closely related species: E. regificella Sircom, presently only recorded from Great Britain, E. geminatella (Herrich-Schäffer), stat. rev. (= E. nieukerkeni Traugott-Olsen, syn. nov.) and E. tengstromi nom. nov. (= E. magnificella Tengström, 1848, nec Duponchel, 1843). The latter two species are widely distributed e.g. in Central Europe, the range of E. tengstromi extending to Japan. The species are diagnosed and illustrated. Life history records indicate that the species have, at least to some extent, different host plant preferences: Luzula sylvatica is recorded as the host plant of E. regificella and E. geminatella, of which the latter probably exploits other host plants as well. L. pilosa is the only known host plant of E. tengstromi in Europe, with further host plants recorded in Japan. Neotypes are designated for Elachista regificella Sircom and Poeciloptilia geminatella Herrich-Schäffer.


1996 ◽  
Vol 13 (2) ◽  
pp. 85-94
Author(s):  
Endah Wahyuningsih ◽  
◽  
Eny Faridah ◽  
Budiadi Budiadi ◽  
Atus Syahbudin ◽  
...  

Ketak (Lygodium circinatum (Burm.) Sw. is a fern plant and its growth requires other plants as a host plant for climbing of tendrils to get light. Information of vegetation association of host plant is needed, due to it is considered to have an influence on growth and productivity. This data and information is important to develop a strategy of ketak for cultivation and conservation. This research was aimed to determine vegetation association of ketak host plant in its habitat. The study applied purposive systematic sampling by survey technique based on altitude i.e. 0-249, 250-499 and 500-750 m asl. There are 10 of observation plot with dimension of 20 m x 20 m. In each plot, an analysis of vegetation association of ketak host plant to determine association between species, type of interaction and index of association between species of ketak host plant. The results showed that vegetation association of ketak host plants in each altitude classification which had a positive and strong association were 14 pairs species in altitude of 0-249 m asl, and 8 pairs species in altitude 250 – 499 m asl, and also in altitude 500 – 750 m asl had 15 pairs species. Altitude 500 - 750 m asl, shows the association of vegetation with the highest combination of species pairs.


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