Adult female and neonate larval plant preferences of the generalist herbivore, Epiphyas postvittana

The polyphagous leafroller moth, Epiphyas postvittana, is a pest of many fruit crops in New Zealand. Since the larva is highly mobile, host selection in this insect may involve both the adult female and the larva. In order to test the relative importance of the adult female and the neonate larva in the selection of host plants, the ovipositional preferences of females, and the preferences or acceptances of neonate larvae towards 26 plant species, consisting of 15 plants considered hosts and 11 not considered hosts, were investigated. In the ovipositional tests, the mean preferences of females for hosts and non-hosts were very similar. In contrast, larvae showed a significantly greater mean preference or acceptance towards hosts than to non-hosts, in both choice and no-choice bioassays, respectively. There were highly significant correlations between the preferences and acceptances of larvae for plants in the choice and no-choice tests. In the no-choice tests, there was a highly significant correlation between the acceptances of neonate larvae towards plants after one and three days (i.e., acceptances changed little over time). Moreover, in these no-choice tests, there was a significant negative correlation between larval acceptance at 1 day and larval mortality after 3 days; that is, the less acceptable a given plant at 1 day, the more likely larvae would fail to establish, feed, and survive on it by three days. Female and larval preferences towards the various plants were also negatively correlated. Together, these data suggest that the selection of a plant for the neonate larva to feed on is largely governed by the preferences of the larva, rather than by the preferences of the female. However, selection of a plant for oviposition by the female, may be important in host selection for reasons unrelated to larval preferences, for example, by encouraging dispersal, perhaps to other plant species, of the neonate larvae and thereby decreasing intersibling competition.     

The influence of tactile and other non-chemical factors on the ovipositional responses of the generalist herbivore Epiphyas postvittana

A bioassay to test the ovipositional responses of the generalist herbivore, Epiphyas postvittana, was developed, and various non-chemical factors that influenced the laying, and number of eggs laid, by females were tested. In choice experiments using various models, surface texture was found to be an important factor influencing ovipositional behaviour, with females preferring to lay on smoother rather than rougher surfaces. Another surface texture feature that influenced oviposition was a raised wax ridge on a smooth surface. The wax ridge stimulated more eggs to be laid within close proximity to the ridge. Observations of females showed that the increased numbers of eggs laid on models with a wax ridge resulted not from increased landing, time spent, or numbers of eggs laid per ovipositional bout, but rather through an increased probability of ovipositing after landing on models with a wax ridge compared to models without the ridge. Spatial features of the models were also found to influence egglaying by females. Females showed a tendency to lay on the upper rather than the lower surface of models, although this appeared to depend upon how stimulatory the upper surface of the model was. Females also laid more eggs on models with a dense array of leaves than on models with a more spread-out array.     

Interactions between male moths of the lightbrown apple moth, Epiphyas postvittana (Walker) (Lep.: Tort.), landing on synthetic sex pheromone sources in a wind-tunnel

Abstract. This study was designed to determine whether landings of males of Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae) on synthetic sex pheromone sources are influenced by other males which have preceded them in flying to and landing on the sources. The investigation comprised two separate experiments. In one, using a single pheromone source, insects released singly were compared with insects released in groups of three, and in the other, insects released in groups of five were presented with a choice between two identical sources. The resolution for changes in attractancy was higher in the choice experiment which demonstrated an increase in attraction for a source on which males had already landed and remained whilst the new male flew towards it. A single resident insect increased the source attractancy by a factor of 1.40 and a pair of insects by 1.77 compared with an empty source. With the single sources the data exhibited the same trend but the result was rendered not significant by an insufficient amount of data, although approximately equal times were allocated to each experiment. To achieve a significant result with the single sources at least 6 times as much data would need to be collected.     

Volatiles from Botrytis cinerea‐infected and healthy berries of Vitis vinifera influence the oviposition behaviour of Epiphyas postvittana

Interactions among plants, plant‐feeding insects, and plant – pathogenic fungi are partially mediated by volatile compounds. Herbivorous insects use sensory cues to choose host plants for feeding and/or oviposition that are likely to support survival and development of progeny. It is known that some fungus‐induced alterations in plants can modify plant volatiles, which are recognized by the olfactory receptors of the insect, either as an attractant or as a deterrent. We tested for the presence of behaviour‐modifying volatiles emanating from the berries of Vitis vinifera L. (Vitaceae) infected with Botrytis cinerea Pers. (Helotiales). We tested the olfactory behaviour of adults of Epiphyas postvittana Walker (Lepidoptera: Tortricidae) to these volatiles using two‐choice and wind‐tunnel experiments. We hypothesized that olfactory cues influence E. postvittana's oviposition behaviour. We found that volatiles emanating from B. cinerea‐infected berries did not significantly attract the gravid females of E. postvittana; consequently, they laid significantly fewer eggs on infected berries. Furthermore, significantly fewer females of E. postvittana were found attracted to infected berries in the wind tunnel assay. Ethanol and 3‐methyl‐1‐butanol were abundant in B. cinerea‐infected berries. Oviposition assays made with laboratory standards of ethanol and 3‐methyl‐1‐butanol confirmed their role in regulating the olfactory behaviour of E. postvittana site selection.     

Parasitoid exploitation of the seasonal variation in host plant volatile emission for herbivore location

Volatile compounds from the apple, Malus domestica Borkh. (Rosaceae), change considerably as the season progresses, and this is successfully exploited by the female codling moth Cydia pomonella L. (Lepidoptera, Tortricidae), as it searches for oviposition sites. In this study, we investigated the effect of seasonal emissions of apple fruit volatiles on the host location behaviour of a parasitoid of the codling moth larvae, Hyssopus pallidus (Askew) (Hymenoptera: Eulophidae). In dual choice olfactory bioassays, the behaviour of the parasitoid in response to apple cues was observed over the complete 2003 growing season. Our results show that codling moth infested apples evoked a strong response from the parasitoid at the beginning of the season, until July. Then, attraction dropped drastically, increasing again at the beginning of August. At the end of the growing season, just prior to harvest, infested apples hardly evoked any behavioural response. Interestingly enough, mid‐season emissions of healthy apples were per se attractive to the parasitoid, and even preferred over volatiles from infested apples. Simultaneous volatile collections from healthy apples on twigs in the field were analysed throughout the season, showing that the overall quantity of headspace volatiles peaks at the beginning of June and mid‐August. The seasonal volatile emission is correlated with the behaviour of the parasitoid during the fruit ripening stage. The results are discussed in relation to the use of H. pallidus as a potential biocontrol agent, in order to enhance current integrated pest management (IPM) programs.     

Screening for resistance in apple cultivars to lightbrown apple moth, Epiphyas postvittana, and greenheaded leafroller, Planotortrix octo, and its relationship to field damage

The mature leaves of 38 apple (Malus domestica Borkh.) (Rosaceae) cultivars were screened for resistance to laboratory colonies of Epiphyas postvittana (Walker) and Planotortrix octo Dugdale (Lepidoptera: Tortricidae) by measuring larval survival and development rate, and pupal weight, in no‐choice laboratory bioassays in early summer. There were few cultivar effects on larval mortality but Nevis 1, A40R04T119, and ‘Sir Prize’ reduced survival of E. postvittana. Effects on development time and weight were correlated, and were integrated into a single measure of resistance R_c. R_c varied greatly between cultivars for both leafroller species, and identified 15 and 11 cultivars with partial resistance to E. postvittana and P. octo, respectively. A further experiment with three of the cultivars in midsummer, using the laboratory colonies in comparison with new colonies (from field collected larvae), produced similar results for E. postvittana, but there was no survival of new colony P. octo larvae on two cultivars. These results for P. octo are consistent with other recent research showing extreme cultivar resistance and critical colony and seasonal influences. A series of 4‐year field trials with the 38 cultivars showed poor correlation between laboratory and field resistance for the dominant leafroller species in the field, E. postvittana. The combined data, however, identified ‘Red Dougherty’, ‘Sir Prize’, and A40R04T119 as potentially useful in breeding for resistance to this species. The implications of these findings for integrated pest management (IPM) programmes and for the breeding of leafroller‐resistant apple cultivars are discussed.     

Effect of a vertical object on the sex pheromone-mediated flight and landing behaviors of the male lightbrown apple moth,Epiphyas postvittana (walker) (Lepidoptera: Tortricidae)

A small (2.5-cm-wide) vertical (10-cm-high) white object influenced the sex pheromone-mediated flight and landing behaviors of maleEpiphyas postvittana. When the vertical object was positioned on a horizontal surface to the side (3–5 cm) and upwind of a pheromone source (in the middle of the surface), the distribution of landing positions of males on the surface was different from that when the object was not present; males tended to land in positions skewed toward the side of the source that the object was on. The closer the object was positioned to the source, the greater the number of males that landed on the object (rather than on the horizontal surface). This difference in landing positions (when the object was present) corresponded with changes in the flight tracks; the tracks of males flying to the surface with an object were skewed toward the object and had higher amplitude intertrack reversal distances than the tracks of males flying to a surface without a vertical object. Positioning of a vertical object progressively upwind of the source resulted, apparently, in decreased effects on the landing (and presumably flight) behavior of males. The effect of the vertical object on the flight and landing behaviors of males corresponded largely with changes in pheromone plume structure (visualized with smoke) induced by the extra turbulence in the airflow over the source. Thus it appears that the vertical object influences the behavior of maleE. postvittana largely through the olfactory sensory modality. However, when a clear, Mylar object, in place of the white object, was placed on the surface, more males landed on the Mylar object (than did on the white object), suggesting that the vertical object may also influence the behavior of males through the visual modality.     

Olfactory orientation of the truffle beetle, Leiodes cinnamomea

Although the truffle beetle, Leiodes cinnamomea, inflicts substantial damage to the ripe stage of fruiting bodies of the economically important black truffle (Tuber melanosporum), it is not attracted by ripe truffle odours. Rather, male beetles are attracted to infested truffles only in the presence of female beetles, suggesting that the former employ a pheromone to locate truffles over short distances. In contrast, female beetles show no attraction to infested or uninfested truffles, suggesting that they employ other cues, possibly linked to odours emitted by truffles prior to the ripe stage. We hypothesize that the chemical composition of truffle volatiles changes over the life of the truffle fruiting body, being attractive to insects early on and to mammals just prior to decomposition.     

Age-related flight and reproductive performance of the light brown apple moth, Epiphyas postvittana

The relationship between flight activity, reproduction and age of Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae) was studied using tethered flight assays. Flights began on the day of emergence, peaking on days four and five in females and on day five in males, and lasted for nine to ten days. The development of flight capacity was well synchronised with the build-up and decline of reproductive behaviours (calling, mating and oviposition). Flights of E. postvittana are thus inter-reproductive, and there is no obvious pre-oviposition period. Males were more active than females as 45–50% of male moths in comparison to 15–18% of female moths were capable of prolonged flights during the peak activity period. The results suggest that flights of E. postvittana are appetitive flights to a large extent, but it is suggested that some individuals may migrate, as there is no diapause in this species. The sexual dimorphism of flight capacity is discussed in relation to those of other tortricids and Lepidoptera in general.

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Zusammenfassung Die Beziehungen zwischen Flugaktivität, Fortpflanzung und Alter von Epiphyas postvittana (Walker) (Tortricidae) wurden untersucht mit Hilfe von angebudenen Flugapparaten. Flüge begannen am Tage des Schlüpfens, mit einen Maximum am vierten und fünften Tag bei Weibchen und am fünten Tag bei Männchen, und dauerten neun bis zehn Tage. Die Entwicklung des Flugvermögens war gut mit der Zu- und Abnahme des Fortpflanzungsverhaltens (Rufen, Kopulieren und Eiablage) korreliert. Flüge von E. postivittana finden also während der Fortpflanzungsperiode statt, und es gibt keine deutliche Periode vor der Eiablage. Männchen waren aktiver als Weibchen: 45–50% der Männchen verglichen mit 15–18% der Weibchen waren zu langen Flügen während der maximalen Aktivitätsperiode fähig. Das Ergebnis deutet an, das Flüge von E. postvittana im grossen Masse Appetenzflüge sind, doch es wird auf die Möglichkeit hingewiesen, dass einige Individuen wandern können, da die Art keine Diapause hat. Der Geschlechtsdimorphismus in der Flugaktivität wird diskutiert und verglichen mit dem anderer Tortriciden und der Lepidoptera allgemein.

     

Delayed mating reduces fecundity of blackheaded fireworm, Rhopobota naevana, on cranberry

This study examines the effects of delayed mating on two successive generations of blackheaded fireworm, Rhopobota naevana Hübner (Lepidoptera: Tortricidae), a pest of cranberry, Vaccinium macrocarpon Aiton (Ericaceae). The first (spring) generation produces eggs that hatch soon after oviposition, whereas the second (summer) generation produces mostly diapause eggs. Unmated female and male moths were placed together on the first, second, fourth, sixth, or eighth day after emergence. In the first generation, incidence of mating was greatest in the 1-, 2-, and 4-day treatments then declined as female survival decreased. In the second generation, incidence of mating was lowest in the 1-day treatment and greatest in the 2-, 4-, and 6-day treatments. Most second generation females in the 6- and 8-day treatments survived to mate. The mean oviposition period was 2.6 days for first generation females and 4.1 days for second generation females. Fecundity of singly mated females in both generations declined as age at mating advanced, but the pattern of decline differed between generations. First generation females that were mated on the first or second day laid more eggs than those mated on the fourth, sixth, or eighth day, and the number of infertile eggs increased as age at mating advanced. Fecundity of second generation females declined more gradually and the number of infertile eggs was greatest for females mated on the first, sixth, or eighth day. A consequence of the marked decline in fecundity due to mating delays in the first generation was that mean fecundity of the entire group of first generation females was ca. 13% less than that of the group of second generation females. On cranberry farms, pheromone-mediated mating disruption can prevent or delay mating of blackheaded fireworm. If the frequency of disrupted (prevented and delayed) matings is similar in the two generations, fewer eggs will be laid in the first generation than in the second.     

Resident spiders as predators of the recently introduced light brown apple moth,Epiphyas postvittana

The invasive light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), has not reached damaging levels on crops in California (USA), suggesting that its populations and impact are limited by generalist natural enemies. In a series of laboratory experiments, we examined resident spiders as predators of E. postvittana larvae on two host plants, the ornamental Australian tea tree, Leptospermum laevigatum (Gaertn.) F. Muell (Myrtaceae), and the weed French broom, Genista monspessulana (L.) L.A.S. Johnson (Fabaceae). Of three abundant spider species in Australian tea tree, two hunting spiders measurably reduced the numbers of E. postvittana larvae and plant damage, whereas a web‐weaving spider had no detectable impact. The adult stage of the dominant hunting spider Anyphaena aperta Banks (Anyphaenidae) consumed E. postvittana larvae, but neither large nor small juveniles had statistically detectable effects on numbers of larvae. However, plant damage was reduced in the presence of large juvenile A. aperta, suggesting that A. aperta may also have non‐consumptive effects on the feeding behavior of E. postvittana larvae. Anyphaena aperta consumed larvae only when larval densities exceeded a low threshold in a functional response experiment, leading to a type III functional response. Adult A. aperta showed no preference for different E. postvittana instars, whereas Cheiracanthium mildei L. Koch (Miturgidae), an abundant hunting spider on French broom, showed a partial preference for late‐instar larvae. The generalist feeding habits of the spiders may have precluded strong prey preferences. Results show that hunting spiders may help limit E. postvittana populations in California, and that they may in turn reduce the impact of E. postvittana on its host plants.     

The role of availability of food and water to the adult Epiphyas postvittana, the light brown apple moth, in its reproductive performance

Female Epiphyas postvittana (Lepidoptera, Tortricidae) moths were able to lay fertile eggs without feeding, but they require water to achieve their full reproductive potential. Fecundity of moths given water from emergence was not different from that of moths fed with 30% honey solution. Deprivation of feeding during the early stage (up to three days after emergence) showed no significant decrease in fecundity provided that honey solution was available from the age of four days after emergence. Starved moths laid less than 30% of the number of eggs laid by those fed with honey solution or water. Fecundity was correlated with moth weight at emergence when moths were fed with water or honey solution, but not when no food or water was provided. Moths of both sexes fed on honey solution copulated less frequently, lost body weight at a lower rate and had a greater longevity, compared with those fed with water or nothing. These results are discussed in relation to the reproductive strategy of this species.

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Zusammenfassung Weibliche Motten der Art Epiphyas postvittana (Lepidoptera, Tortricidae) legten fruchtbare Eier ohne Nahrung aufzunehmen, brauchten jedoch Wasser, um ihr volles Fortpflanzung — Potential zu erreichen. Fruchtbarkeit von Motten, denen Wasser von der Zeit des Schlüpfens an gegeben wurde, unterschied sich nicht von der Fruchtbarkeit der Motten, die mit einer 30 prozentigen Honiglösung gefüttert wurden. Nahrungsentzug während der frühen Entwicklung (bis zu drei Tagen nach Schlüpfen) führte nicht zu einer Reduktion der Fruchtbarkit, vorausgesetzt dass Honiglösung von einem Alter von vier Tagen nach Schlüpfen angeboten wurde. Hungernde Motten legten weniger als 30% der Eier als mit Honiglösung oder Wasser gefütterte Motten. Fruchtbarkeit war korreliert mit dem Gewicht der Motten zur Zeit des Schlüpfeus, wenn die Motten mit Wasser oder Honiglösung gefüttert wurden, jedoch nicht, wenn weder Nahrung noch Wasser angeboten wurde. Mit Honiglösung gefütterte Motten beiderlei Geschlechts kopulierten weniger häufig, verloren Gewicht langsamer und lebten langer als mit Wasser oder nicht gefütterte Motten. Die Ergebnisse werden diskutiert in Bezug auf die Fortpflanzungsstrategie der Art.

     

Oviposition preference and larval performance of Epiphyas postvittana (Lepidoptera: Tortricidae) on Botrytis cinerea (Helotiales: Sclerotiniaceae) infected berries of Vitis vinifera (Vitales: Vitaceae)

In this paper we tested the behavior of gravid Epiphyas postvittana in selecting the most‐appropriate site for oviposition thus benefitting offspring performance. Our hypothesis was built on Jaenike's preference–performance hypothesis (also referred to as the “mother‐knows‐the‐best” hypothesis). To test this, we used the interacting Epiphyas postvittana, its host Vitis vinifera, and the pathogenic microbe Botrytis cinerea system. Populations of E. postvittana and B. cinerea often exist concurrently on V. vinifera in Australasia and their interaction and mutual influence are currently being explored, although the suggestion presently is that the relationship between E. postvittana and B. cinerea is mutualistic. We tested the effect of volatiles from B. cinerea‐infected berries and uninfected (control) berries of V. vinifera on the oviposition behavior of E. postvittana. We also characterized the effects of B. cinerea infection on the berries of V. vinifera on the growth and development of E. postvittana. Contrary to the preference–performance hypothesis, oviposition choices made by gravid E. postvittana did not result in the best offspring survival, development, and performance. The preference for oviposition by E. postvittana was strongly influenced by the olfactory and tactile cues. She laid fewer eggs on B. cinerea‐infected berries compared to uninfected berries of V. vinifera. The larvae of E. postvittana showed no preference to uninfected berries of V. vinifera. The larvae fed on B. cinerea‐infected berries of V. vinifera showing greater survival rate, shorter time to pupation, greater pupal mass, and on becoming adults they laid more numbers of eggs than the larvae that were enabled to feed on uninfected berries. The larvae of E. postvittana transport the conidia of B. cinerea and transmit grey‐mould disease to uninfected berries of V. vinifera.     

Development, fecundity and survival of the herbivore Lymantria dispar and the number of plant species in its diet

ABSTRACT.

• 1 Larval gypsy moth Lymantria dispar (L.) mortality depends upon the number and type of plant species consumed as well as the sequence in which they are consumed.
• 2 When a two-species diet is composed of a favourable and an unfavourable species, larval mortality is higher on the two-species diet than on the diet of the favourable species alone.
• 3 When a two species diet is composed of a favourable and unfavourable coniferous species, larval mortality is higher on the single conifer species diet than on the two-species diet.
• 4 Two-species diets, in which one species is a conifer, produce individuals with a greater fecundity than diets of either species alone.
• 5 The influence of diets composed of two favourable species, on development, size and fecundity, depends both on the relative quality of each of the two plant species and which of the two is consumed by older instars.

     

Antennal and behavioural response of codling moth Cydia pomonella to plant volatiles

Identification of host volatile compounds attractive to codling moth Cydia pomonella, a most important insect of apple, will contribute to the development of safe control techniques. Synthetic apple volatiles in two doses were tested for antennal and behavioural activity in codling moth. Female antennae strongly responded to (Z)3‐hexenol, (Z)3‐hexenyl benzoate, (Z)3‐hexenyl hexanoate, (±)‐linalool and E,E‐α‐farnesene. Two other compounds eliciting a strong antennal response were the pear ester, ethyl (E,Z)‐2,4‐decadienoate, and its corresponding aldehyde, E,E‐2,4‐decadienal, which is a component of the larval defence secretion of the European apple sawfly. Attraction of codling moth to compounds eliciting a strong antennal response was tested in a wind tunnel. Male moths were best attracted to a blend of (E,E)‐α‐farnesene, (E)‐beta‐farnesene and ethyl (E,Z)‐2,4‐decadienoate. The aldehyde E,E‐2,4‐decadienal had an antagonistic effect when added to the above mixture.     

A test of fruit varieties on entry rate and development by neonate larvae of the codling moth,Cydia pomonella

The rate of entry by neonate larvae of the frugivorous codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), into fruit material was investigated. We used no‐choice bioassays in climate‐controlled rooms to assay larval entry across four host plant species (apple, pear, quince, walnut) and three varieties within a single fruit species (apple). Larvae successfully entering apples were reared to adulthood, and we collected tissue samples from apples which were successfully colonized in order to determine sucrose concentrations. This information was used to evaluate differences in adult moth size, development time, and pulp sucrose concentration due to apple variety. Four important findings emerged: (1) neonate larvae had the highest frequency of entry (86% of larvae) into apple fruits, compared with pear (78%), quince (56%), and walnut (32%); (2) the frequency of larval entry into immature apples differed across apple varieties, and larval entry rate was highest in variety Golden Delicious (72%), compared with Granny Smith (46%) and Red Delicious (64%); (3) on average, adult moths were larger and development times were shorter on the variety with the highest entry frequency (Golden Delicious); and (4) apple pulp sucrose concentrations were higher for Golden Delicious (17.5 μg mg^?1) than for either Granny Smith (15.9 μg mg^?1) or Red Delicious (15.1 μg mg^?1) varieties, which correlates positively with entry and development data. We conclude that host fruit species and varietals within a species affect the entry rate of neonate codling moth larvae in no‐choice assays. We hypothesize that larval development is influenced by mean sucrose concentrations or other phytochemical differences associated with host fruit varieties.     

The effects of mating,exogenous juvenile hormone and a juvenile hormone analogue on pheromone titre,calling and oviposition in the omnivorous leafroller moth (Platynota stultana)

Mating in Platynota stultana resulted in the termination of calling, the gradual reduction of pheromone in the pheromone glands to non-detectable levels (<0.1 ng/♀) within 14 h, and oviposition of the first batch of eggs 20–24 h after copulation. Decapitation of virgin females resulted in a similar decline in pheromone titre, and also eliminated oviposition and calling. Pheromone production appears to be controlled via the head. Mating probably terminates neural or hormonal input required for pheromone production and/or removes neural or hormonal inhibition of pheromone degradation. A juvenile hormone analogue (ZR-512) and juvenile hormones I, II and III applied exogenously to virgin females elicited oviposition comparable to mated females and terminated calling within 48 h. The juvenile hormone analogue also appeared to block pheromone production in virgin females. These results suggest that juvenile hormone may be involved in the switch from virgin to mated behaviour in this species.     

Influence of crop variety and fertilization on oviposition preference and larval performance of a generalist herbivore,the true armyworm,Mythimna unipuncta

The relationship between oviposition preference and offspring performance of herbivores is an essential question in the field of plant–insect interactions and may have important implications on integrated pest management practices. Here, we investigated the preference–performance relationship of a generalist herbivore, the true armyworm, Mythimna unipuncta (Haworth) (Lepidoptera: Noctuidae, Leucaniini). We evaluated the effect of crop species, cultivars, and fertilization rate on host use by adult and larval M. unipuncta in both laboratory and field experiments. Female M. unipuncta preferred to oviposit on cereals (Triticum aestivum L., Hordeum vulgare L., Zea mays L., all Poaceae) compared to oilseed (Brassica napus L., Brassicaceae) or pulse (Pisum sativum L., Fabaceae) crops. The preference–performance relationship was examined further on four cereal crops, spring wheat (T. aestivum cv. CDC Go), winter wheat (T. aestivum cv. CDC Buteo), feed barley (H. vulgare cv. Xena), and malt barley (H. vulgare cv. Copeland). Feed barley was the least preferred cereal by female moths but resulted in the highest larval performance of all tested plants suggesting that females did not select the host on which their offspring performs best, based on nutrient content. In contrast, late-instar larvae selected the hosts, feed barley and malt barley, on which they performed the best, suggesting that larvae have a more active role in host selection for development, compared to adult females. The addition of fertilizer to host plants did not influence adult female oviposition preference. Larvae reared on plants treated with the half (70 mg N) or full (140 mg N) dose of fertilizer resulted in heavier pupae, compared to those reared on unfertilized plants, regardless of crop variety. However, under field conditions fertilization did not enhance larval performance on feed barley plants. The generalist herbivore M. unipuncta does not exhibit the ‘mother knows best’ principle on the tested hosts and potentially employs a bet-hedging strategy instead.