Mite Load Research Articles

Personality and ectoparasitic mites (Hemipteroseius adleri) in firebugs (Pyrrhocoris apterus)

Individuals of the same species often consistently differ in their behaviour across time and context. These stable differences are usually termed ‘animal personality’. Parasitism is known to significantly influence the evolution of animal personality at least in part because more explorative individuals may meet parasites more frequently than less explorative ones. Previously, we have demonstrated that consistent individual differences (i.e. boldness, activity, exploration) can be measured in firebugs. As continuation, we examined here the relationship between firebug personality traits and their ectoparasitic mite loads in a wild population. We showed that bugs that behaved in a more explorative way have more mites and we also found a marginally significant interaction between sex, boldness and activity: bolder and more active female firebugs were more infected. In addition, we experimentally tested whether an artificial infection causes any alteration in the bug’s behaviour and whether there is any relationship between firebug personality and immune response. This treatment did not induce any alteration in bugs’ personality. We found that bugs become more explorative but less active when repeating the experiment, but at the same time all personality traits (boldness, activity and exploration) were repeatable. Furthermore, firebugs with a stronger immune response behaved more boldly but also less actively.

Relationships between beak condition, preening behavior and ectoparasite infestation levels in laying hens

The effects of beak condition on ectoparasite populations and preening in laying hens were investigated. Beak-trimmed and beak-intact caged Hy-Line W-36 hens were infested with either chicken body lice or northern fowl mites using a 2 × 2 factorial design with 4 replicate cages (each containing 2 hens)/treatment: 1) BTL (beak-trimmed lice-infested); 2) BTM (beak-trimmed mite-infested); 3) BIL (beak-intact lice-infested); and 4) BIM (beak-intact mite-infested). Mite scores and lice numbers were estimated weekly. Hens were video recorded the wk before infestation and at wk 6 and 9 post-infestation. Time spent preening on 6 body areas and in total were analyzed using a repeated measures ANOVA. There was a wk × beak condition interaction for lice loads, with BTL harboring approximately 17 times more lice than BIL from wk 7 to 10 post-infestation (P < 0.0001). Beak condition affected mite loads (P < 0.0001), with BTM having a higher mite score (3.8 ± 0.26) than BIM (1.4 ± 0.26). At peak infestation, BTL spent more total time preening (P = 0.02, s ± SE: 232.1 ± 37.6) than prior to infestation (33.9 ± 37.6) and directed their preening behavior towards the vent. In contrast, BIL (73.9 ± 37.6), BTM (9.4 ± 1.6), and BIM (8.6 ± 1.6) did not increase total time spent preening over pre-infestation levels (103.6 ± 37.6, 5.8 ± 1.6, 6.7 ± 1.6 respectively), although BTM did redirect their preening behavior toward the vent. This study confirmed previous studies showing that an intact beak is important for reducing ectoparasite infestations. Preening behavior increased in response to lice infestation, but only in beak-trimmed hens; preening behavior and louse load were correlated at peak infestation. In contrast, mite infestation did not lead to increased preening, and there was no correlation between preening and mite load. However, both lice- and mite-infested hens directed preening behavior predominantly towards the vent where these parasites are typically found.

The influence of Nosema (Microspora: Nosematidae) infection on honey bee (Hymenoptera: Apidae) defense against Varroa destructor (Mesostigmata: Varroidae)

The objectives of this study were to quantify the costs and benefits of co-parasitism with Varroa (Varroa destructor Anderson and Trueman) and Nosema (Nosema ceranae Fries and Nosema apis Zander) on honey bees (Apis mellifera L.) with different defense levels. Newly-emerged worker bees from either high-mite-mortality-rate (high-MMR) bees or low-mite-mortality-rate (low-MMR) bees were confined in forty bioassay cages which were either inoculated with Nosema spores [Nosema (+) group] or were left un-inoculated [Nosema (−) group]. Caged-bees were then inoculated with Varroa mites [Varroa (+) group] or were left untreated [Varroa (−) group]. This established four treatment combinations within each Nosema treatment group: (1) low-MMR Varroa (−), (2) high-MMR Varroa (−), (3) low-MMR Varroa (+) and (4) high-MMR Varroa (+), each with five replicates. Overall mite mortality in high-MMR bees (0.12±0.02 mites per day) was significantly greater than in the low-MMR bees (0.06±0.02 mites per day). In the Nosema (−) groups bee mortality was greater in high-MMR bees than low-MMR bees but only when bees had a higher mite burden. Overall, high-MMR bees in the Nosema (−) group showed greater reductions in mean abundance of mites over time compared with low-MMR bees, when inoculated with additional mites. However, high-MMR bees could not reduce mite load as well as in the Nosema (−) group when fed with Nosema spores. Mean abundance of Nosema spores in live bees and dead bees of both strains of bees was significantly greater in the Nosema (+) group. Molecular analyses confirmed the presence of both Nosema species in inoculated bees but N. ceranae was more abundant than N. apis and unlike N. apis increased over the course of the experiment. Collectively, this study showed differential mite mortality rates among different genotypes of bees, however, Nosema infection restrained Varroa removal success in high-MMR bees.

Effects of Ectoparasitism on Behavioral Thermoregulation in the Tropical lizards Anolis cybotes (Squamata: Dactyloidae) and Anolis armouri (Squamata: Dactyloidae)

A febrile response, or a raised body temperature in response to infection, has been widely documented in various species of reptiles in laboratory trials. However, whether and how behavioral fever is achieved in nature remains almost entirely unknown. Here, we examine whether two species of lizard in the cybotoid clade of Hispaniolan trunk-ground anoles (Anolis cybotes and Anolis armouri) change their basking behavior in response to infestation by the chigger mite, Eutrombicula alfreddugesi. We examined body temperature and basking behavior in wild populations of A. cybotes and A. armouri from four localities that spanned a 2,000-m elevational transect in the Sierra de Baoruco, Dominican Republic. Although basking rate increased with elevation, we found that it did not correlate with mite load. Body temperature was also unrelated to parasite load. Thus, we found that E. alfreddugesi infestation did not induce behavioral fever in these anoles. We found a strong altitudinal pattern in chigger infestations: Infestations levels were highest in lizards from mid-elevation and dropped dramatically at low and high elevation (particularly in the latter). We discuss possible mechanisms for this altitudinal pattern in chigger infestation and discuss the relationship between infection and behavioral thermoregulation in lizards.

Crowding honeybee colonies in apiaries can increase their vulnerability to the deadly ectoparasite Varroa destructor

When humans switched from hunting honeybee colonies living scattered in the wild to keeping them in hives crowded in apiaries, they may have greatly increased disease transmission between colonies. The effects of clustering colonies were studied. Two groups of 12 colonies, with hives crowded or dispersed, were established in a common environment and left untreated for mites. Drones made many homing errors in the crowded group, but not in the dispersed group. In early summer, in both groups, the colonies that did not swarm developed high mite counts, but the colonies that swarmed maintained low mite counts. In late summer, in the crowded group but not in the dispersed group, the colonies that swarmed also developed high mite counts. All colonies with high mite counts in late summer died over winter; all colonies with low mite counts in late summer survived over winter. Evidently, swarming can reduce a colony’s mite load, but when colonies are crowded in apiaries, this mite-load reduction is erased as mites are spread through drifting and robbing.

Seasonal Variation of Honeybee Pathogens and its Association with Pollen Diversity in Uruguay.

Honeybees are susceptible to a wide range of pathogens, which have been related to the occurrence of colony loss episodes reported mainly in north hemisphere countries. Their ability to resist those infections is compromised if they are malnourished or exposed to pesticides. The aim of the present study was to carry out an epidemiological study in Uruguay, South America, in order to evaluate the dynamics and interaction of honeybee pathogens and evaluate their association with the presence of external stress factors such as restricted pollen diversity and presence of agrochemicals. We monitored 40 colonies in two apiaries over 24months, regularly quantifying colony strength, parasite and pathogen status, and pollen diversity. Chlorinated pesticides, phosphorus, pyrethroid, fipronil, or sulfas were not found in stored pollen in any colony or season. Varroa destructor was widespread in March (end of summer-beginning of autumn), decreasing after acaricide treatments. Viruses ABPV, DWV, and SBV presented a similar trend, while IAPV and KBV were not detected. Nosema ceranae was detected along the year while Nosema apis was detected only in one sample. Fifteen percent of the colonies died, being associated to high V. destructor mite load in March and high N. ceranae spore loads in September. Although similar results have been reported in north hemisphere countries, this is the first study of these characteristics in Uruguay, highlighting the regional importance. On the other side, colonies with pollen of diverse botanical origins showed reduced viral infection levels, suggesting that an adequate nutrition is important for the development of healthy colonies.

Juvenile sexual dimorphism, dichromatism and condition-dependent signaling in a bird species with early pair bonds

AbstractSexual selection in juvenile vertebrates is a rare and seldom studied phenomenon. Bearded Reedlings are passerines that form stable, life-long pair bonds within a few weeks after fledging. We investigated the degree to which juvenile Bearded Reedlings are sexually dimorphic and whether they possess condition-dependent ornaments. We found significant intersexual differences in the bill reflectance, reflectance and size of eumelanin-based plumage traits (lore and back patch) and morphological traits. Females that were in better body condition had longer tails and bills with greater red chroma, and lore size was negatively related to the occurrence of chewing lice. In males, body condition was positively related to melanic back patch length. Moreover, a positive relationship between bill color and feather mite load in males suggests a symbiotic, rather than parasitic, relationship. Our study provides the first evidence that sexually dimorphic traits in immature birds with pair bonds have the potential to signal condition and resistance to parasites.

Effectiveness of mite-impermeable covers: a hypothesis-generating meta-analysis.

Asthma is a heterogeneous disease. The subject of mite allergen control has evolved into a debate dominated by a Cochrane review by Gøtzsche and Johansen (Cochrane Database of Systematic Reviews, 2008, Art. No: CD001187). A not well-discussed aspect of that study is the selection by those authors of a univariate meta-analysis including various interventions. This study extends the meta-analysis by Gøtzsche and Johansen and aims to generate hypotheses on the effectiveness of various bedding interventions, including the coverage of all bedding elements. Trials were selected based on environmental criteria. The interventions were classified according to the number of barriers used. Standardized mean differences yielded the mite load, three physiological outcomes and asthma symptom scores. The influence of covariates was examined with a mixed-effect model using the metafor package for meta-analysis in R. Twelve trials included 1187 observations. The interventions included one barrier or product (six trials), two barriers or partial control (four trials) and three barriers or integral control (two trials). The exposure data showed considerable heterogeneity (I(2) = 93%). The risk of bias significantly (P = 0.04) influenced the final load, the square root of the interaction between the baseline load and the type of intervention as well (95% CI: -0.66 to -0.07 μg/g; P = 0.02). Changes in load showed similar tendencies. Health outcomes showed moderate to considerable heterogeneity (physiological outcomes I(2) = 44-94%; symptom score I(2) = 93%). A meta-regression of bedding interventions indicates that integral control most significantly reduced mite load when the load was high at baseline. The number of trials was too small to allow an appropriate examination of health outcomes. Future studies are suggested to test the hypothesis that allergic patients benefit from integral control when the baseline mite load is high.

Longevity of starved bumblebee queens (Hymenoptera: Apidae) is shorter at high than low temperatures

Northern bumblebees (Hymenoptera: Apidae) with annual lifecycles depend both on energy stores remaining in their fat body after diapause and a few spring flowering plants. Most temperate bumblebees emerge gradually over several months after winter depending on the species and within species on the location of the overwintering chamber (hibernaculum). Weather can either delay or promote emergence and nectar resources are needed to fuel flight at low ambient temperatures to find a nest site. Several phoretic mites use queens for transportation and have synchronized life cycles with their host species. Their presence on the body of bumblebees is usually harmless but can become harmful when the number of mites increases to hundreds per individual bee. High numbers of mites on queens may also indicate the queens are in poor condition. The effect of temperature and mite load on the time for which queens can survive (d) during a 25-day period of starvation were determined using newly emerged spring queens of B. lucorum. Queens collected from various locations in SW Finland were divided into four groups taking into account their initial load of Parasitellus fucorum mites: (A) 15°C and provided with only water; (B) 24°C and provided with only water; (C) 15°C and provided with pollen and nectar; (D) 24°C and provided with pollen and nectar. There were mites on 65% (50 out of 77) of the queens. All of the fed queens survived and starved queens died, with those kept at 24°C dying approximately 8 days before those kept at 15°C. Queen weight or mite load had no effect on the length of the period for which they survived and there was no difference in the weights of the queens in the different mite load classes. Asynchrony between plants and insect as well as increased frost damage due to climate change may affect nectar availability in spring. Therefore, the survival and long term viability of bumblebee populations should be monitored during variable spring conditions.

Spatial aggregation of phoretic mites on Bombus atratus and Bombus opifex (Hymenoptera: Apidae) in Argentina

Mites have been observed on the bumblebee’s body and inside their nest for over 150 years, and parasitic relationships between them have occasionally been reported. One of the most interesting animal associations between mites and bees is phoresy. At present, no study has evaluated the distribution patterns of phoretic mites on bumblebees nor the factors that might be influencing such association. The main goal of this research was to determine whether an aggregation of external mites on bumblebees is influenced by (a) the phoretic mite load per bee, (b) the host species, (c) the caste of bumblebee, (d) the interaction between mite load and bee species, and (e) the presence of a suitable physical place for the mites to accommodate on the bee body. The following mite species were recorded on Bombus atratus and Bombus opifex: Kuzinia laevis, Kuzinia americana, Kuzinia affinis, Kuzinia sp., Pneumolaelaps longanalis, Pneumolaelaps longipilus, Scutacarus acarorum, and Tyrophagus putrescentiae. Our results indicate that Kuzinia mites have a strong preference for a particular region on the propodeum, which has shorter hairs than on most areas of the body. In addition, generalized linear model analysis demonstrated that mite aggregation was influenced by the caste and host species.

Sprint speed is related to blood parasites, but not to ectoparasites, in an insular population of lacertid lizards

Parasites are able to negatively affect the locomotor performance of their hosts, and consequently, their biological fitness. In this study, we examine the relationship between parasitism and burst speed in an insular population of Lilford’s Wall Lizard (Podarcis lilfordi (Günther, 1874)). Podarcis lilfordi is normally infected with haemogregarine blood parasites and mites in our study location, Aire Island (Balearic Islands, Spain). Unlike the results from other studies on lizards, we found a significant negative correlation between intensity of infection by haemogregarines and burst speed. Body condition is also significantly related to burst speed. Thus, lizards with a lower blood parasite load and better body condition show a faster sprint speed. Intensity of infection by haemoparasites shows a lack of correlation with both body condition and mite load. Our results are compared with those from other lizard species living in different habitats. We discuss the influence of insular environmental conditions on locomotor performances, such as low predation pressure, lack of competitors, and high lizard densities.

Do infections lead to higher feather mite loads in birds? A test with mycoplasmal conjunctivitis in House Finches (Haemorhous mexicanus)

Abstract. Current evidence suggests that the health effect of avian feather mites is minimal. However, feather mites can still proliferate without effective preening, such as might occur during sickness. House Finches (Haemorhous mexicanus) are prone to infection by Mycoplasma gallisepticum, symptoms of which include conjunctivitis. Impaired vision and lethargy associated with the disease may limit preening ability. We examined trapping data from a 4-year study of Mycoplasma infection dynamics in House Finches in Atlanta, Georgia, to determine whether birds with conjunctivitis had higher feather mite loads. Abundance of feather mites (Proctophyllodes spp.) and conjunctivitis severity were visually scored on >800 House Finches of known age and sex. Feather mite abundance showed a distinct seasonal pattern: mite loads increased in July and remained high through January. Limiting the analyses to these months, we found that average mite scores were higher in birds with (n = 94) than in those without (n = 275)...

Colorful displays signal male quality in a tropical anole lizard

Parasites influence colorful ornaments and their behavioral display in many animal hosts. Because coloration and display behavior are often critical components of communication, variation in these traits may have important implications for individual fitness, yet it remains unclear whether such traits are signals of quality in many taxa. We investigated the association between ectoparasitic mite load and the color and behavioral use of the throat fan (dewlap) by male Anolis brevirostris lizards. We found that heavily parasitized lizards exhibited lower body condition, duller dewlaps, and less frequent dewlap displays than less parasitized individuals. Our results thus suggest that highly parasitized individuals invest less in both ornamental color and behavioral display of that color. Because the two components of the signal simultaneously provide information on male quality, this study provides novel support for the long-standing hypothesis that colorful traits may function as social or sexual signals in reptiles.

Varroa-Virus Interaction in Collapsing Honey Bee Colonies

Varroa mites and viruses are the currently the high-profile suspects in collapsing bee colonies. Therefore, seasonal variation in varroa load and viruses (Acute-Kashmir-Israeli complex (AKI) and Deformed Wing Virus (DWV)) were monitored in a year-long study. We investigated the viral titres in honey bees and varroa mites from 23 colonies (15 apiaries) under three treatment conditions: Organic acids (11 colonies), pyrethroid (9 colonies) and untreated (3 colonies). Approximately 200 bees were sampled every month from April 2011 to October 2011, and April 2012. The 200 bees were split to 10 subsamples of 20 bees and analysed separately, which allows us to determine the prevalence of virus-infected bees. The treatment efficacy was often low for both treatments. In colonies where varroa treatment reduced the mite load, colonies overwintered successfully, allowing the mites and viruses to be carried over with the bees into the next season. In general, AKI and DWV titres did not show any notable response to the treatment and steadily increased over the season from April to October. In the untreated control group, titres increased most dramatically. Viral copies were correlated to number of varroa mites. Most colonies that collapsed over the winter had significantly higher AKI and DWV titres in October compared to survivors. Only treated colonies survived the winter. We discuss our results in relation to the varroa-virus model developed by Stephen Martin.

Altered species interactions at forest edges: contrasting edge effects on bumble bees and their phoretic mite loads in temperate forest remnants

Abstract The way in which species interactions are altered at habitat edges is an emerging concern in conservation biology, with some theories predicting edge‐affected habitats to be less stable and exhibit intensified species interactions relative to interior habitats. One little‐studied interaction is phoresy, where an individual of one species attaches itself to an individual of another species for the purpose of dispersal. Bumble bees (Bombus spp.) are important crop pollinators around the world and at least 10 species of phoretic mites have been associated with various bumble bee species. Here, we investigated changes in the abundance of the introduced European B. terrestris across forest‐grassland edges in the Southern Alps of New Zealand, and concomitant changes in the phoretic mite loads on these mobile pollinators. Bumble bees penetrated up to 250 m inside forest fragments, with abundance declining with distance from the anthropogenic matrix habitat. By contrast, phoretic mite loads increased towards the forest interior. Overall, phoretic mite loads on B. terrestris were greatest in the forest canopy, suggesting that this species interaction is intensified in natural habitat compared to that in the anthropogenic land use surrounding forest fragments. Our data indicate that phoretic loads on bumble bees are elevated in forest canopies. The functional significance of altered bumble bee – mite interactions for pollination services at forest edges remains to be tested.

Host selection of ectoparasitic gamasid mites on Tylonycteris pachypus and T. robustula

Correlations of two species of gamasid mites (Macronyssus pararadovskyi and M. radovskyi) and their bat hosts (Tylonycteris pachypus and T. robustula) were studied by field surveys and indoor behavioral experiments. The wild data indicated that mite load was positively correlated with body condition index of female T. pachypus hosts (Spearman: r (s)=0.55, P<0.01, n=24). Whereas, mite loads had no correlation with body condition indexes of male T. pachypus and all T. robustula hosts (P>0.05). Indoor original host infection showed that mites preferred male T. pachypus and T. robustula hosts. The infection percentages on male hosts were significantly higher than those on female hosts [T. pachypus: male (58±12)%, female (42±12)%, (t=-3.6, df=31, P<0.01); T. robustula: male (63±11)%, female (37±11)%, (t=-6.1, df=26, P<0.001)]. Using M. pararadovskyi (original host T. pachypus) to across infect T. pachypus and T. robustula, we found that mites significantly preferred the original host (t=9.1, df=29, P<0.001). The infection percentages of T. pachypus, and T. robustula were (71±13)% and (29±13)%, respectively. Our results indicated that mite loads of the two bat species were not correlated with body condition indexes of hosts. However, these mites presented different host sexual preferences, and the mites of T. pachypus presented specific host species preferences.

The Effect of Exogenous Testosterone on Ectoparasite Loads in Free‐Ranging Western Fence Lizards

Numerous factors impact the dynamics of host-parasite relationships, such as host sex, hormonal state, reproductive condition, host health, and behavior. In particular, males from a variety of taxa frequently carry heavier parasite burdens than females, particularly during breeding season when testosterone concentrations are elevated. Using western fence lizards (Sceloporus occidentalis), we tested the hypothesis that high circulating testosterone concentrations in male lizards induce high tick and mite loads. We implanted male lizards with either testosterone or control implants in the field during the spring, when tick and mite loads are highest. One month later, testosterone-implanted males had significantly higher tick loads, but lower mite loads, than control males. These results suggest that testosterone differentially impacts ectoparasitic acarine burdens. Testosterone may modulate aspects of lizard physiology and behavior that enhance or diminish parasitism by certain acarines during periods of peak reproductive effort.

Argasid and spinturnicid mite load on swarming bats in the Tatra Mountains, Poland

Altogether 445 bats, representing nine species, caught during swarming in the Lodowa Cave in Mount Ciemniak, Western Tatra Mountains, southern Poland, were examined for ectoparasitic mites. In total, 259 spinturnicid (Spinturnix mystacina, S. andegavinus, S. kolenatii, S. plecotinus and S. myoti) and 95 argasid (Carios vespertilionis) mites were collected from seven bat species, Myotis myotis, M. mystacinus, M. brandtii, M. daubentonii, Eptesicus nilssonii, Plecotus auritus, and Vespertilio murinus. There were sex-based differences in the prevalence of mites in some hosts but no differences in their mean intensity and there was no observed relationship between the number of mites and the condition of the bats. The prevalence of mites differed significantly between years in E. nilssonii. The results suggested a very low mite load on swarming bats that had no impact on the body condition of bats.

A scientific note on the ant pitfall for quantitative diagnosis of Varroa destructor

The mite Varroa destructor is a global challenge for apiculture and accurate quantification crucial for adequate and timely pest management. However, foraging ants are regularly found in hives and may interfere with mite diagnosis. Here, we quantify for the first time the impact of ants. We expect lower mite numbers on bottom boards with foraging ants and that estimates of phoretic mites are ant independent. From July to August 2007–2009, the experiments were conducted with 64 queenright honey bee colonies (predominantly Apis mellifera carnica, Table I). One apiary was used for 3 years, but each time, new colonies were monitored. All colonies (~11 frames of bees, 6–10 brood frames) were housed in Dadant hives (12 frames) with bottom board inserts for mite quantification (Imdorf et al. 2003) and placed in groups of four or five each on hive stands with four steel polders (50 cm aboveground). All colonies were treated in summer and fall using formic and oxalic acid (Imdorf et al. 2003). To quantify the impact of ants, we added traps (water-filled buckets [∅=20 cm]) to each of the four steel polders of the hive stands. At least once a month, water was refilled, and the surrounding vegetation was cut. The controls remained without traps. Quantifications were conducted weekly by removing the bottom board inserts and counting all mites and ants. In 2009, we also collected weekly 200 bee workers from the brood nests of 18 colonies for 8 weeks to evaluate the number of phoretic mites following Ritter and Ruttner (1980). For that purpose, nine colonies received traps (= treatments), and nine remained without (= controls) for 4 weeks; then, the groups were exchanged by relocating traps. Thus, we obtained from the same colonies mite infestation loads from both bottom board counts and phoretic mite estimates with or without ant traps. We also monitored all stands to investigate whether they were exposed to ant foraging. Ants were collected for taxonomic identification using morphometrics (Seifert 2007). We performed Kruskal–Wallis and Mann–Whitney U post hoc tests to compare ant and mite numbers. To test whether there is a regression between ant and mite numbers, we constructed a Linear Mixed Model (LMM), with log-transformed V. destructor numbers as the dependent variable, log-transformed ant numbers as fixed effect and colony as random effect, resulting in normally distributed residuals:

Small-cell comb does not control Varroa mites in colonies of honeybees of European origin

We tested the idea that Varroa destructor can be controlled in colonies of the European subspecies of Apis mellifera by providing them with combs built of small cells, in which immature mites might have difficulty developing for lack of space. We established seven pairs of equal-size colonies that started out equally infested with mites. In each pair, one hive contained only standard-cell (5.4 mm) comb, and the other contained only small-cell (4.8 mm) comb. We measured the colonies' mite loads at monthly intervals across a summer. No differences arose between the two treatment groups in their mean mite loads (mites per 100 worker bees or mite drop per 48 h). We suggest that providing small-cell combs did not inhibit mite reproduction because the fill factor (thorax width/cell width) was only slightly higher in the small cells than in the standard cells (79% and 73%, respectively).