Effects of protein and carbohydrate levels on survival,consumption and gonad index in adult sea urchin Strongylocentrotus purpuratus (Stimpson 1857) from Baja California,Mexico

A greater understanding of dietary protein and carbohydrate levels with regard to gonad production in Strongylocentrotus purpuratus would increase our nutritional knowledge of this sea urchin and guide the development of formulated diets for such aquaculture target species. A total of 255 purple sea urchins were captured from Ensenada Bay, Mexico, and maintained in 200‐L tanks for 9 weeks. Formulated diets that contained 30%, 26%, 23%, 20% and 17% of protein and 42%, 46%, 50%, 54% and 58% carbohydrates were offered ad libitum. Survival was affected by diets; urchins that were fed high‐protein–low‐carbohydrate diet experienced decreased survival. No significant differences were found in gonad index, but gonad production efficiency was lower in urchins that were fed a medium‐low‐protein–medium‐high‐carbohydrate diet. Urchins that were fed high carbohydrate levels utilized protein more efficiently and showed better digestibility of the diet and protein. These data suggest that all of our diets support gonad growth, but in terms of consumption, a diet that contains protein levels of 17% and 23% with carbohydrate levels of 50% and 58% are beneficial for S. purpuratus.     

The development of a formulated feed containing Ulva (Chlorophyta) to promote rapid growth and enhanced production of high quality roe in the sea urchin Tripneustes gratilla (Linnaeus)

This study investigated growth and gonad production of Tripneustes gratilla fed four protein‐rich artificial diets supplemented with varying amounts (0%, 5%, 15% and 20% weight/weight (w/w); designated 0, 5, 15 and 20U, respectively) of the macroalga Ulva over a 12‐week period. Gonad size, texture, colour and a number of production performance parameters were quantified and compared with urchins fed fresh Ulva (FU) and a combination of FU and artificial feed (FB). All artificial diets significantly (P ≤ 0.05) increased gonad somatic indices (GSI) compared with the FU treatment. The 20U treatment increased GSI by 205% by week 9, compared with a 57% increase in the GSI of urchins fed FU. Gonad colour was calculated using three colour parameters, namely L* (lightness), a* (redness) and b* (yellowness). Whereas L* and a* values did not differ significantly between treatments, b* values for all treatments, with the exception of the 20U and FB treatments, were significantly (P ≤ 0.05) lower or less yellow than the FU treatment by week 12. These results show that we have successfully formulated a feed (20U) which can produce commercially acceptable gonads in terms of both size and colour, indicating the potential for this artificial feed to support commercial echinoculture.     

Increased gonad growth of the purple sea urchin (Strongylocentrotus purpuratus) fed the giant kelp (Macrocystis pyrifera) and the sea lettuce (Ulva lactuca) enriched with nutrients

Adult (Strongylocentrotus purpuratus) purple sea urchins were fed giant kelp (Macrocystis pyrifera) and sea lettuce (Ulva lactuca) macroalgae that were unenriched and enriched with nutrients. Urchins were fed over 10 weeks (5% body weight per day) under laboratory conditions to determine the effect of macroalgae species and treatment (enriched and unenriched) on growth, gonad index and gonad quality. Significant differences were observed when urchins were fed enriched Macrocystis pyrifera (MPE). Gonad weight increased from 0.7 ± 0.1 g (mean ± SD) to 5.9 ± 1 g, and gonad index increase from 3.5 ± 1.5% to 14.9 ± 2.3% over 10 weeks. Significant differences were also noted in gonad quality, and gonad colour and firmness were better in urchins that were fed unenriched M. pyrifera (MPUE) and MPE – whereas texture did not differ between M. pyrifera treatments and unenriched U. lactuca (ULUE). With regard to taste, gonads were sweeter in MPE‐fed individuals. Enriched U. lactuca (ULE) failed to grow gonads significantly; as a result, their quality was unacceptable for the market. These results suggest that S. purpuratus experience increased gonad production and quality in short periods when fed nutrient‐enriched M. pyrifera.     

Effect of different feed formulations on feed efficiency, gonad yield and gonad quality in the purple sea urchin Heliocidaris erythrogramma

The nutritive values of three pelleted prepared diets, based on animal (AP), vegetable (VP) and yeast protein (YP) were studied for the sea urchin Heliocidaris erythrogramma (Val.). Fresh macroalga Ulva australis was used as a natural control diet. Triplicate groups of five animals were fed one of the four diets ad libitum every second day for 85 days. Sea urchins fed pelleted feeds had significantly higher food consumption rates (dry basis) and significantly lower total and protein absorption efficiencies compared with the algal diet. The gonad yield and gonad production efficiency in sea urchins fed the natural diet were significantly higher compared with initial group (gonad yield only) and urchins fed animal and vegetable diets, but did not differ significantly from those of the animals fed the yeast diet. Percent protein and lipid in the gonads were not affected by the dietary source. The taste and smell of gonads were generally better in sea urchins collected from the wild or fed yeast and natural diets than in sea urchins fed animal and vegetable diets. The animal protein diet was the most stable in seawater while the yeast protein diet had the poorest water stability. The results of this study suggest that development of a more stable, single‐cell, protein‐based diet has a potential to promote gonad production of H. erythrogramma.     

Gonad quality of sea urchin Paracentrotus lividus cultured in an offshore pilot‐scale trial on the south‐east Italian coast

A pilot project aimed at testing roe enhancement strategies based on offshore Paracentrotus lividus cultures was conducted off the south‐east coast of Italy (Apulia Region). Adult sea urchins were reared in sea cages located 700 m offshore at a depth of 12 m for 3 months. The animals were fed once a week on two formulated diets, prepared mixing nutrients with agar 20 g/Kg and differing only in terms of the protein source: anchovy flour (Diet A) or krill flour (Diet K). At the end of the rearing trial, the gonad somatic index of sea urchins fed on formulated diets significantly exceeded that of wild sea urchins. Total FAA content in the gonads of wild sea urchins and Diet A‐fed sea urchins was similar, whereas in Diet K‐fed sea urchins it was significantly higher. In terms of fatty acids, the gonads contained SFAs, MUFAs and PUFAs. In visual and sensory assessment of gonads by panel test and electronic nose, the gonads of reared sea urchins were rated as being of better size, while no differences were recorded for coloration, taste and odour. This study shows that under these experimental conditions, commercial‐grade Paracentrotus lividus roe enhancement can be achieved after 3 months in sea cages.     

Effects of dietary fish oil and soya bean lecithin on gonad index,colour and biochemical composition of the purple sea urchin,Strongylocentrotus purpuratus (Stimpson 1857)

The effects of increasing soya bean lecithin (SL) levels (0%, 2% and 4% of diet dry matter, DM) at two fish oil (FO) levels (0% and 3% DM) on gonad index, colour and biochemical composition of Strongylocentrotus purpuratus were evaluated using a 3 × 2 factorial design with six iso‐nitrogenous formulated diets. All diets generated an increase in gonad index of more than 9%. Dietary FO had a positive effect on diet digestibility and accumulation of proteins in the gonad. Soy lecithin did not affect gonad composition, but improved its coloration, decreased gonad feed conversion ratio and increased gonad protein efficiency. There was a clear effect of diets on sea urchins gonad protein, ash and fatty acid content, in particular, decreasing the n‐3/n‐6 ratio associated with a decrease in 20:5n‐3 when SL levels increased. Nevertheless, 22:6n‐3 levels increased by week 12 in all treatments, and diets with SL increased the content of 20:4n‐6 in gonads. A decrease in bitter‐tasting amino acids such as histidine, cysteine, valine and methionine was observed in all treatments with a concomitant increase in isoleucine levels. We recommend using a diet containing 3% of FO and 2% of SL to increase food consumption, diet digestibility, improving marketable gonad colour and an increasing gonad n‐6 fatty acids and C22:6n‐3. In addition, the present study paves the way for future research in the use of FO and SL as an additive in diets for S. purpuratus towards the goal of increasing gonad size and nutritional quality.     

Carotenoid composition of a New Zealand (Evechinus chloroticus) and an Australian (Heliocidaris erythrogramma) sea urchin in relation to gonad colour

Sea urchins are commercially harvested for their edible gonads, also known as roe or uni. Most species, particularly those from the Northern hemisphere are reported to exhibit limited variation in gonad colour, which is proposed to be due to carotenoid pigments. The commercially harvested species from New Zealand, Evechinus chloroticus, and from Australia, Heliocidaris erythrogramma, however, exhibit considerable gonad colour variation, ranging from a culinary desirable light yellow/orange to an undesirable brown. Gonads from E. chloroticus and H. erythrogramma were characterized spectrophotometrically and the carotenoid content extracted and analysed by reversed‐phase high‐performance liquid chromatography. The main carotenoid found in the gonads of both species was 9′‐cis‐echinenone, with lower levels of all‐trans‐echinenone, lutein and isozeaxanthin. Carotenoid composition contributed to the yellow/orange colour components of the gonads, but was not correlated with the darker roe coloration observed in some E. chloroticus individuals. Our results highlight important considerations relating sea urchin gonad coloration to carotenoid content and as such will provide useful information for the future aquaculture and processing of these two species.     

The use of stable isotope ratios δ13C and δ15N to track the incorporation of Ulva and other important dietary ingredients into the gonads of the sea urchin Tripneustes gratilla

In this study, we demonstrate how stable carbon (C) and nitrogen (N) isotope analysis can be used to estimate the allocation of specific dietary ingredients, incorporated into four artificially formulated feeds supplemented with varying amounts of dried seaweed Ulva armoricana (0, 50, 150 and 200 g/kg), to the production of gonads by Tripneustes gratilla over a 20‐week growth trial. Results indicate that U. armoricana is an important dietary ingredient for gonad production, accounting for an average of 37.33 ± 1.03% of the isotopic signal recorded for gonads at the end of the growth trial. This is significantly more than fish meal and soya, which only contributed an average of 11.40 ± 1.81 and 3.80 ± 0.09%, respectively, of the isotopic signal of the gonads. Maize and wheat each account for almost 25% of all the dietary ingredients used to formulate the feeds, but their relative contribution to gonad production only averaged 8.55 ± 0.58 and 3.80 ± 0.05%, respectively, among the diets. This indicates that, at least for gonad development, these ingredients may not be required at such high levels. These findings support previous data on the importance of Ulva in abalone and urchin diets, and demonstrate the value of stable isotope analysis for assessing the contribution of specific dietary ingredients in new feed formulations, particularly where growth of specific tissues is being investigated.     

A comparison of the effect of urchin size and diet on gonad yield and quality in the sea urchin <Emphasis Type="Italic">Evechinus chloroticus</Emphasis> Valenciennes

We compared the gonad-enhancing effects of two diets (NIWA and NIFA diets) in two size classes of sea urchins (Evechinus chloroticus): small and large urchins with a test diameter of 75.6 ± 1.2 mm and 93.8 ± 0.5 mm, weighing 174.8 ± 7.9 g and 315 ± 5.6 g, respectively. After eight weeks being fed prepared diets, urchin gonad index (GI) had significantly surpassed that of the initial and final samples of wild urchins. Urchins in the NIWA/small treatment had a larger GI than the NIFA/small and NIFA/large treatments. The NIWA/large treatment had a larger GI than the NIFA/large treatment. The overall percentage increase in GI for the NIWA/small, NIWA/large, NIFA/small and NIFA/large treatments were 183%, 135%, 132% and 85%, respectively. In terms of gonad colour (CIELAB), there were no significant differences in gonad redness (a*) or yellowness (b*) between experimental treatments, but there was a significant difference in gonad lightness (L*) with small urchins fed both diets having lighter-coloured gonads than the large urchins fed both diets. Sensory assessment of gonads revealed that gonads from small urchins fed both diets were rated as being of better colouration and more uniform in colour than gonads from large urchins. Gonads of urchins fed the NIFA diet were rated as being less bitter and of better overall taste than gonads from urchins fed the NIWA diet. This study shows that feeding prepared diets to E. chloroticus can significantly increase gonad yield but that different diets can affect the magnitude of GI increase and the taste of gonads, and that smaller urchins appear more suitable for gonad enhancement.     

Effect of three diets on the gametogenic development and fatty acid profile of Paracentrotus lividus (Lamarck, 1816) gonads

In this study, the effects of three diets were investigated to enhance Paracentrotus lividus production for commercial purposes. P. lividus were fed ad libitum for 80 days with: diet A—fresh Codium tomentosum Stackhouse, 1797; diet B—formulated using a jellified mix of macroalgae and vegetables, including C. tomentosum (20%), Coralina sp. Linnaeus, 1758 (17%), cabbage Brassica oleracea var. capitata Linnaeus, 1753 (30%), carrot Daucus carota Linnaeus, 1753 (30%) and agar (3%) as a gelling agent. Diet C consisted of maize Zea mays Linnaeus, 1753 (56%) and New Zealand spinach Tetragonia tetragonoides (Pallas, 1781) Kuntze, 1891 (44%). Their effects on the gonadal and somatic growths, gonadosomatic index (GI) and gametogenesis were evaluated, as well as on the total lipid content and fatty acid composition of sea urchin's gonads. Diet A provided high values of eicosapentaenoic acid (EPA). Gonads of sea urchins fed with diet A were found mostly in growth and maturation stages of gametogenesis and showed the lowest lipid content. Sea urchins fed with diet B presented their gonads in the reabsorption stage and had the highest values of omega‐3 polyunsaturated fatty acids (PUFAs). Sea urchins fed with diet C were in the early stages of gametogenesis and had the highest values of lipid content, plus omega‐6 PUFAs. Once as an ingredient in a balanced mix with vegetables, C. tomentosum can be a key factor to the development of new promising high‐quality and low‐cost feed for P. lividus roe enhancement.     

Experimental rearing of the sea urchin Paracentrotus lividus fed with discards of the lettuce Lactuca sativa in a sea‐based system

Small‐sized specimens (test diameter: 16.64 ± 0.93 mm, mean ± SE) of the sea urchin Paracentrotus lividus were fed with fresh discards of the lettuce Lactuca sativa during a 24‐week experiment in a sea‐based system. At the end of the experiment, stock survival was high (88.8 ± 6.6%). Sea urchin test diameter and total weight grew by 35% and 56%, respectively, while gonad somatic index, after an initial decrease, increased by 3.2%. Moreover, more than 90% of specimens achieved the gonad colour that the market demands. These results support the exploitation of L. sativa as the main ingredient in a manufactured diet for echinoculture of P. lividus. Employing diets formulated with discard ingredients, combined with a low‐cost sea‐based rearing system, could be a suitable approach for sustainable management of echinoculture.     

Formulated Feed Supports Weight Gain and Survivorship in Juvenile Sea Urchins Lytechinus variegatus

In adult sea urchins, formulated feeds can support both weight gain and gonad production; however, studies demonstrating the effects of formulated feeds on juvenile sea urchin growth are limited. In this study, juvenile sea urchins (test diameter: 3.20–7.33 mm, N = 12 per treatment) were reared individually in artificial seawater and fed with one of four experimental feeds: (1) mixed‐taxa algal biofilm (MTAB), (2) freeze‐dried MTAB, (3) a commercial, small‐mammal feed (Friskies^® cat treats), or (4) a semipurified feed formulated for sea urchins. The MTAB and sea urchin feed supported weight gain and survival throughout the study; however, those individuals fed with the sea urchin feed exhibited a short lag period at the onset of feeding. This short lag period may be, in part, because of an initial lack of attraction of the urchins to the formulated feed. Furthermore, we hypothesize that gut physiology or gut flora must acclimatize to a new diet (all sea urchins were reared initially on the MTAB diet). The freeze‐dried MTAB and mammal feed did not support substantial weight gain. This study suggests that sea urchin juveniles as small as 3–4 mm can utilize formulated feeds for growth.     

Effect of polysaccharides extracts of algae Ulva rigida on growth,antioxidant, immune response and resistance of shrimp,Litopenaeus vannamei against Photobacterium damselae

This study was carried out to investigate the effect of water‐soluble polysaccharides extract of algae Ulva rigida (WPU) as dietary supplement on growth performance, antioxidant enzyme activity, lysozyme and phenoloxidase activity, and resistance of shrimp (Litopenaeus vannamei) subjected to bacterial infection with Photobacterium damselae. Three replicate groups of shrimp (1.0 g) were fed four diets containing four levels, 0 or control, 0.5, 1 and 1.5 g/kg of WPU for 8 weeks over the growth trial. Thereafter, 30 shrimps from each dietary treatment were infected with bacteria P. damselae to evaluate disease resistance of infected shrimp. The results of this study showed that WPU was effective as a growth promoter for L. vannamei. The best growth rate was observed in shrimp fed 1.5 g/kg of WPU diet. Regarding antioxidant defences, the diets supplemented with three levels of WPU stimulated glutathione peroxidase and catalase activates in experimental shrimps. MDA content of L. vannamei‐fed diet containing WPU 1.5 and WPU 1.0 was lower than WPU 0 and WPU 0. 5 diets. Also, lysozyme and phenoloxidase activities of shrimp receiving WPU at 1.0 and 1.5 level were significantly higher than those fed WPU 0 and WPU 0.5 diets. In addition, using WPU extract in all diets decreased mortality in L. vannamei in a dose‐dependent manner after challenge with P. damselae. These results suggest that incorporation of water‐soluble polysaccharides from green algae U. rigida at 1.5 g/kg doses improves growth and antioxidant activity and enhances the immune responses in shrimp L. vannamei.     

Evaluation of dried macrophytes as an alternative diet for the rearing of the sea urchin Paracentrotus lividus (Lamarck, 1816)

The aim of this work was to assess the potential use of different dried macroalgae as food in the rearing of Paracentrotus lividus. Growth, consumption and food conversions were compared in adult sea urchins fed with fresh or dried thalli of four macroalgae species. Six experimental diets were tested: (a) fresh Palmaria palmata; (b) fresh Saccharina latissima; (c) dry P. palmata; (d) dry S. latissima; (e) dry Laminaria digitata and (f) dry Grateloupia turuturu. Linear growth rates were similar for all treatments. Specific growth rate was higher in sea urchins fed with fresh P. palmata, but no difference was found between animals fed with fresh S. latissima and those fed with dried diets. Regarding daily food consumption (DFC), sea urchins consumed the same amount of dried macroalgae as fresh but exhibited a higher food conversion efficiency (FCE) when fed with fresh P. palmata. However, this FCE was only significantly higher when compared to sea urchins fed with dry L. digitata. Dried G. turuturu is not a suitable diet due to its rapid degradation after rehydration. The results suggest that P. lividus adults can be reared on dried macroalgae thalli without detriment to their somatic growth, especially over short periods. The low cost of feeding sea urchins with this diet could help small shellfish farmers to diversify their production into echinoculture.     

Protein and energy digestibility and gonad development of the European sea urchin Paracentrotus lividus (Lamarck) fed algal and prepared diets during spring and fall

Protein and energy are two of the main limiting factors for sea urchin growth. However, the requirement of daily protein and energy to maximize gonadal production is still unknown. Paracentrotus lividus were fed three experimental diets: Ulva lactuca, Gracilaria conferta and a prepared diet for 2 months in the fall of 1999 and spring of 2000. Sea urchins from a laboratory‐cultured population of equal age, weight and test diameter were used. Apparent digestibility coefficients (ADC%) for protein and energy, using acid‐insoluble ash as a marker, were measured for all experimental diets. Apparent digestibility coefficients for protein was high (>75%) for all diets. Energy digestibility varied among the diets and was lowest for G. conferta (50–62%). The three diets contained varying digestible protein (DP) to digestible energy (DE) ratios of 25, 26 and 12 mg kJ^?1 for U. lactuca, G. conferta and the prepared diet respectively. Digestible protein intake was similar for all treatments, but DE intake was greater for sea urchins fed the prepared diet in both seasons. As a result, the gonad production was significantly higher for urchins fed the prepared diet, suggesting that energy was limiting in the algal diets. Paracentrotus lividus spawned during the spring experiment, resulting in protein loss in all treatments. Protein loss was lowest in the sea urchins fed the prepared diet. Enhanced gonadal growth and gamete development of P. lividus resulted from the higher dietary energy content of the prepared diet.     

Feeding time,frequency and ration affect growth and energy allocation in young adults of the sea urchin Lytechinus variegatus

In a 62‐day growth trial, wild caught Lytechinus variegatus (ca. 18 g, 35 ± 2 mm dia.) were fed as follows: (i) ration equivalent to 3% of average body weight proffered once daily in the morning (AM treatment); (ii) ration equivalent to 3% of average body weight proffered once daily in the evening (PM treatment); (iii) ration equivalent to 1.5% of average body weight proffered twice daily (every 12 h, AM/PM treatment); (iv) ration equivalent to 3% of average body weight proffered in the evening on alternate days (EODSR/PM); or (v) ration equivalent to 6% of average body weight proffered in the evening on alternate days (EODDR/PM). At 30 and 62 days, wet weight gain among urchins fed daily was significantly higher than that of urchins fed on alternate days, regardless of ration size. At 62 days, reduced gonad dry matter production and gonad index were observed among individuals fed on alternate days, regardless of ration size. At 30 and 62 days, feed conversion ratio was optimized among individuals fed daily and in the EODSR/PM treatment. These data suggest that, for culture of L. variegatus, daily feeding will optimize growth, gonad production and feed efficiency regardless of ration size or time of feeding.     

Effect of feed deprivation and refeeding on the MYP gene expression of the sea urchin (Strongylocentrotus intermedius)

To determine the main expression site of major yolk protein (MYP) gene and the mechanisms for adaptation to starvation and refeeding in Strongylocentrotus intermedius, MYP mRNA expression amounts were analysed using a real‐time RT‐PCR. The results showed that MYP could be transcribed in the intestine, stomach, gonad and coelomocytes, and that the intestine was the main expression site of MYP gene in non‐starved urchins. The MYP synthesis in the intestine decreased during 15 days of starvation (67.70%, 52.58% and 71.35% of the control at 5, 10 and 15 days of fasting respectively) and then increased dramatically by different amounts (the peaks were 2.71‐, 12.16‐ and 7.89‐fold that of the control respectively) during the refeeding stages. Nevertheless, the expression amounts in the gonads did not decline, but increased continuously during all periods of fasting (2.66‐, 3.72‐ and 13.19‐fold that of the control at 5, 10 and 15 days of starvation respectively) and during the refeeding stages. At the end of the recovery feeding experiment, the levels reached 9.58‐, 17.48‐ and 100.69‐fold that of the control. These data suggested that the ‘priority’ strategy for the sea urchin is to reduce MYP expression amounts in the intestine if food is limited and to increase MYP gene expression in the gonad to protect reproductive function.     

The advantages of Ulva (Chlorophyta) as an additive in sea urchin formulated feeds: effects on palatability,consumption and digestibility

The present study was performed to determine whether the palatability, consumption and digestibility of an artificial sea urchin diet could be improved by the addition of a highly preferred seaweed. Four species of macroalgae (Ulva rigida, Ecklonia maxima, Porphyra capensis and Gigartina polycarpa) were assessed by pairwise preference tests. Each macroalgal species was consumed at least once by Tripneustes gratilla and significant preferences always involved Ulva as the most preferred species. Four protein‐rich artificial diets supplemented with varying amounts of Ulva [0, 50, 150 and 200 g kg^?1 designated 0, 5, 15 and 20U, respectively] were then developed and fed to urchins over a 20‐day period. Inclusion of 200 g kg^?1 dried Ulva significantly improved the palatability of the artificial diet and mean dry feed consumption rates were higher in urchins fed the 20U and 15U diets compared with urchins fed diets with a lower Ulva content. Daily digestible protein (DP) intake also differed significantly, with urchins fed the 20U diet having a significantly higher DP intake compared with the 15U, 5U and 0U treatments. These results indicate that inclusion of the palatable seaweed Ulva acted as a feeding stimulant, increasing the acceptability of the diets and boosting protein intake.     

Influence of broodstock diet on somatic growth,fecundity, gonad carotenoids and larval survival of sea urchin

The effects of formulated feeds on Paracentrotus lividus broodstock performances and carotenoid compositions were investigated. Performance of offspring derived from each dietary treatment was compared to determine whether maternal provisioning of nutrients affected offspring development and survival under commercial culture conditions. At the end of the experimental period (3 months), urchins were induced to spawn, relative fecundity measured, and offspring derived from each treatment were reared independently and survival up to competence assessed. Carotenoid composition of the gonads was also measured. Data showed that the highest dietary protein content significantly improved somatic growth, whereas higher lipid content increased gonadal index (GI) consistent with the use of gonads as nutrient storage in sea urchins. Nonetheless, gonad lipid concentration was not significantly different between treatments indicating that higher dietary lipid content favoured gonadal size rather than increase lipid content of the gonadal tissue. Interestingly, GI and fecundity were not correlated, although the latter may have been enhanced by dietary xanthophyll. This suggests the importance of including carotenoids in broodstock diets to enhance hatchery outputs. This study also indicated that, although broodstock diet can influence fecundity, it had no significant impact on larval survival, which could instead be influenced by rearing conditions.