Studies on ticks of veterinary importance in Nigeria. VI. Comparisons of oviposition and the hatching of eggs of Hyalomma species

Fully engorged Hyalomma spp. in Nigeria oviposited greater numbers of eggs than those partially engorged. Hyalomma impressum was a more prolific egg layer than H. rufipes, H. impeltatum and H. truncatum. The variations in the egg output as well as the recognizable peaks in the number of eggs during oviposition were described for each species. No species of Hyalomma below the engorged weight of 0.2 g oviposited; oviposition started with ticks of weight 0.3 g. Eggs produced by ticks weighing below 0.3 g did not hatch; the highest percent egg eclosion occurred with ticks of weight 0.6 g (H. rufipes) and 0.7 g (other Hyalomma species). The pre-oviposition, oviposition and eclosion periods were shortened when eggs were laid and incubated at high temperatures, although the number of oviposited eggs did not increase significantly. At the standard temperature of 24 degrees C, the longest eclosion period was seen in the eggs of H. rufipes (41 days) while those of H. truncatum, H. impressum and H. impeltatum were similar to each other (29 days). Only eggs of H. rufipes hatched at an incubation temperature of 15 degrees C. Eggs of Hyalomma species laid at the same time hatched over a 2--4 day period, except at 15 degrees C when the hatching period of H. rufipes lasted 10 days. The eclosion period was longest in the earlier ovipositions and shorter in the later ones. It is suggested that some intrauterine larval development might have started in the eggs before they were released at a later oviposition period. The percentage mortality of eggs at various temperatures showed that eggs of H. rufipes were more tolerant of low temperatures than those of H. impressum, H. truncatum and H. impeltatum, while the eggs of the latter 3 species were more tolerant of high temperatures than those of H. rufipes. The relevance of these results of the distribution and abundance of the Hyalomma species in Nigeria was discussed.     

The life cycle of Rhipicephalus bursa Canestrini and Fanzago, 1877 (Acarina: ixodidae) under laboratory conditions

The biology of Rhipicephalus bursa has not been thoroughly studied. In the present study R. bursa was bred in the laboratory and its biology worked out.Larvae, nymphs and adult Rhipicephalus bursa ticks were fed on sheep and were held at 28+/-1 degrees C and 89+/-1% relative humidity (RH) in a darkened incubator. The average weight of engorged females was 0.676g (range 0.353-1.128). The average weight of eggs laid by females was 0.344g (range 0.146-0. 554g). The average number of eggs laid was 7527 (range 6263-8860) and this was significantly correlated with the weight of the females. The index of Reproduction Efficiency (number of eggs per g weight of female) was 8469.6. The index of Conversion Efficiency (weight of eggs per weight of female) was 0.5037.Peak daily oviposition, at an average of 840 eggs per female, occurred on the 6th day of oviposition. After Day 6, the rate declined steadily. The average duration of the preoviposition period was 5.1 days (range 4-7 days). The oviposition period averaged 16.5 days (range 12-21 days), and was significantly related to both the weight of the female and the number of eggs laid. The average pre-hatching period was 31.2 days (range 24-45 days). The average feeding time of larvae and nymphs of this two host tick was 15.2 days (range 14-18 days). Female ticks fed for 5.9 days on the average.Heavier nymphs produced females and a shorter premoult period was noted for lighter male nymphs. The males/females ratio was 1.38:1. The time taken to complete the life cycle was on average 142.45 days (range 99-254 days).     

Effect of temperature on transovarial transmission of Babesia bigemina (Smith and Kilborne, 1893) in Boophilus annulatus (Say, 1821)

The effect of the temperature on the transovarial passage of Babesia bigemina has been studied in female Boophilus annulatus during their oviposition. Kinetes of Babesia were present in eggs laid at the temperatures of 16, 20, 26, 28, 30 and 35 degrees C. The rate of infection was temperature dependent. It reached at least 50%, even at low temperatures. The average infection level at 26 and 30 degrees C was 270 kinetes per egg. However, between 20 and 35 degrees C the eggs laid during the first 3 days were parasite free. At 16 degrees C, no kinetes were detected during the first 13 days of oviposition.     

Effect of infection by Babesia spp. on the development and survival of free-living stages of Boophilus annulatus

Oviposition, egg hatching and survival of newly-hatched larvae of Boophilus annulatus were studied in relation to infection by Babesia species and different temperature regimens. Infection of female ticks by Babesia bigemina or B. bovis had no effect on the time elapsed between engorgement and oviposition. The duration of oviposition was shorter in infected females incubated at 25 degrees C or 35 degrees C and infected females laid fewer eggs than the controls. No larvae hatched at 16 degrees C. B. bigemina-infected eggs hatched more quickly than uninfected eggs at 35 degrees C. The hatching percentage of B. bigemina-infected eggs was reduced by 50% at an incubation temperature of 25 degrees C and by 75% at 35 degrees C. At 16 degrees C there was no difference in the duration of survival of infected and non-infected larvae but at 25 degrees C and 35 degrees C the mean survival period of infected larvae was significantly lower than those of controls.     

Oviposition and incubation in Boophilus decoloratus (Koch, 1844) (Acarina: Ixodidae)

Studies on the duration of the oviposition and incubation periods of Boophilus decoloratus (Koch, 1844) revealed that these non-parasitic periods are temperature dependent, increase in temperature causing shortening of the periods. Humidity had no effect on duration of either the oviposition or the incubation periods. The relation between the mass of engorged female ticks and that of the eggs they produced was found to be linear. The viability of eggs produced during the first 13 days of oviposition (at 26 degrees C) was greater than that of eggs laid subsequently. The critical temperature for B. decoloratus eggs was found to be 42 degrees C and they were shown to be unable to take up water vapour from damp atmospheres. Both temperature and humidity affected the hatch of eggs. A simple model of the relations between the physical factors of the environment and the various biological phenomena studied has been given.     

The effect of the ovine host parasitaemia on the development of Babesia ovis (Babes, 1892) in the tick Rhipicephalus bursa (Canestrini and Fanzago, 1877)

Batches of Rhipicephalus bursa adult ticks were fed on two lambs with 10.0% (batch 1) and 0.3% (batch 2) Babesia ovis parasitaemia, respectively. Haemolymph and eggs were checked for parasites daily after detachment, before and after appearance of B. ovis in the lamb's blood.B. ovis kinetes were found in the haemolymph and eggs earlier in the engorged ticks detached before appearance of the parasite in the host blood. Rates of haemolymph and egg infection with B. ovis as well as the percentage of infected eggs were much higher in batch 1 (10% lamb parasitaemia) than in batch 2 ticks (0.3% lamb parasitaemia). In eggs incubated at 28 degrees C the optimal period to look for kinetes seems to be days 4-9. Heavily infected ticks laid fewer less eggs within a shorter oviposition period. Pre-oviposition, pre-hatching periods and egg hatchability were not affected. Various parasitic forms are described in the haemolymph and the eggs.     

The life cycle of Amblyomma tholloni Neumann, 1899 (Acarina: Ixodidae) under laboratory conditions

The durations of the developmental periods of Amblyomma tholloni, recorded at 25°C and 85–87% RH, were longer than those of most other tick species which have been studied under similar conditions. Fully engorged females laid between 2,871 and 10,347 eggs (mean 5,805). Larvae and nymphs attached rapidly and fed successfully on rabbits and sheep. Adults had to be confined on sheep for as long as 14 days before the first attachment occurred and post-attachment mortality was frequently high. Adult females attached in the absence of males, but did not complete feeding. Prefed males were attracted, both on and off the host, by partially fed females and 2,6-dichlorophenol. Extracts of partially fed females were found to contain 2,6-dichlorophenol, which is a commonly occurring sex pheromone in ixodid ticks.     

Life cycle of Hyalomma anatolicum Koch, 1844 (Acari: Ixodidae) fed on rabbits, sheep and goats

Some aspects of the biology of the tick Hyalomma anatolicum fed on rabbits, sheep and goats were studied. The non-feeding stages were maintained under laboratory conditions at 20-36°C and 75% relative humidity. The longest feeding periods of larvae and nymphs of H. anatolicum were observed when fed on rabbits (mean 4.58 ± 0.51 and 7 ± 1.15 days, respectively) while the longest feeding periods of females were observed on goats (9.61 ± 1.21). The pre-oviposition period (4.8 ± 0.42 days) and pre-eclosion periods (mean 21.3 ± 1.16 days) were shortest for females fed on rabbits. Engorged females reached heavier engorgement weights (482.92 ± 88.08 mg), and produced more eggs (4881.8 ± 842.71) when fed on rabbits. However, no significant differences were observed between the percentages hatchability of eggs laid by ticks fed on the three hosts studied. Most (94.31%) of the larvae fed on rabbits underwent a 2-host life cycle, while few (5.69%) of them behaved as a 3-host ticks. Few larvae were able to complete feeding as 3-host pattern on both sheep and goats, while the majority of the larvae failed to complete feeding or died on their way to molt on both sheep and goats.     

Studies on the critical water mass, rehydration capability and potential, acute chill tolerance and supercooling point of Argas (Persicargas) walkerae (Acari: Argasidae)

The critical water mass, defined as the water mass remaining in a dehydrated tick in the non-ambulatory state, differed only slightly between light and heavy mass groups of Argas walkerae and averaged 23.6% and 23.2%, respectively, in males and 28.4% and 28.0%, respectively, in females. All ticks survived dehydration to 50%, 75% or 100% of their critical water mass, and 95% of them rehydrated during their subsequent incubation at 95% relative humidity (RH) and 28 degrees C for 14 days and regained their ambulatory status. Unfed adults were able to balance water loss frequently over a period of several months. When ticks were repeatedly dehydrated at 0% RH for 14 days, females and males suffered 50% mortality after 16 and 19 cycles of de- and rehydration, respectively, over a period of 278 days and 337 days, respectively. Water itself was not attractive to either dehydrated or non-dehydrated ticks and drinking was not observed. After submergence in water for 3 days, most of the dehydrated adult ticks gained mass. Judged by 50% mortality, larvae tolerated short-term extreme chilling to -24 degrees C, nymphs 1 to -22 degrees C, nymphs II to -20 degrees C, females and males to -19 degrees C. None survived tissue freezing. At a chilling rate of 0.3 degrees C/min, mean supercooling points (SCP) ranged from -25.9 degrees C in eggs to -16.5 degrees C in unfed females. The SCP of all other stages was significantly higher than that of eggs. Mean SCPs of unfed adult ticks dehydrated to 50% or 75% of their critical water mass were significantly lower than that of fully hydrated ticks. The SCPs of ticks acclimated by several weeks exposure to 0 degrees C or to 38 degrees C were significantly lower than those of adult ticks kept constantly at 28 degrees C.     

A laboratory comparison of the life cycles of the dog ticks Haemaphysalis leachi and Rhipicephalus sanguineus

Engorged female Haemaphysalis leachi and Rhipicephalus sanguineus as well as their eggs, flat and engorged larvae and nymphs were incubated at combinations of five temperatures and three relative humidities. Mean pre-oviposition periods for H. leachi varied between 4.3 days and 12.1 days and for R. sanguineus between 4.8 days and 21.0 days. Haemaphysalis leachi converted up to 65.7% of their body mass into eggs and produced up to 16.3 eggs/mg body mass, with 4801 eggs the maximum number deposited by a single female. Peak egg production of 520 eggs/day was recorded 3 days after the commencement of oviposition. Rhipicephalus sanguineus converted up to 68.1% of their body mass into eggs and produced up to 17.2 eggs/mg body mass, with a maximum of 3,232 eggs, and peak egg production of 400 eggs/day 4 days after the commencement of oviposition. Mean incubation periods for eggs of H. leachi varied between 15.5 days and 66.7 days, and for R. sanguineus between 19.0 days and 72.0 days. Mean pre-moult periods for engorged larvae and nymphs of H. leachi varied between 14.0 days and 192.0 days, and 13.0 days and 41.0 days respectively, and for R. sanguineus between 9.5 days and 36.5 days, and 15.0 days and 44.5 days respectively. Allowing 7 days for female engorgement and 7 days for hardening of the exoskeletons and mouthparts of each of the three parasitic stages before they attach to a host, the life cycle of H. leachi would require 97-190 days and that of R. sanguineus 99-236 days to complete at the various regimes of temperature and relative humidity. The greatest proportion of H. leachi larvae engorging on mice detached between 18:00 and 19:00 on the first day of detachment and between 06:00 and 08:00 in the morning and 14:00 and 18:00 in the afternoon of the following day, while the greatest proportion of nymphs engorging on dogs detached around 19:00 on the first day of detachment and between 13:00 and 17:00 on the following day. The greatest proportion of R. sanguineus larvae engorging on dogs detached between 11:00 and 21:00 on the second day of detachment, and the greatest proportion of nymphs detached between 03:00 and 5:00 on the second and third days of detachment.     

On-host ecology and off-host survival of the sheep scab mite Psoroptes ovis

These studies were conducted to investigate the possible role of certain aspects of the on-host ecology and off-host survival of the sheep scab mite, Psoroptes ovis, in the dissemination of infestation. All developmental stages of the mite occurred in the fleece both proximally or distal to the skin of infested Merino and Dorper sheep. A larger proportion of mites was present in the fleece of Dorper sheep distal to the skin in the late afternoon and early morning than at other times during the day. Immature and adult mites readily transferred to tufts of wool or hair placed on infested sheep of both breeds. No mites could be found on wool or hair rubbed off onto tree trunks or branches or other structures in enclosures housing heavily infested sheep, nor could any mites be collected from the soil of these enclosures, whereas more than 80% of mites artificially seeded onto soil samples were recovered. The longest mean off-host survival times for larvae, nymphs, and male and ovigerous female mites were recorded at 10 degrees C, and were 9.25 days (RH = 90%), 15 days (RH = 33% and 75%), 10.5 days (RH = 75% and 90%) and 11.25 days (RH = 90%) respectively. Under natural climatic conditions ovigerous females in glass vials containing Merino wool survived for 17 days compared to 15 days for females in vials without wool; this difference was, however, not significant. The mean off-host pre-hatch period for eggs varied between 5.9 days (T = 25 degrees C and RH = 33%) and 22.1 days (T = 10 degrees C and RH = 75%), while the longest time individual eggs took to hatch at the latter temperature and RH was 31 days.     

Effect of temperature on transtadial transmission of Theileria annulata in Hyalomma anatolicum anatolicum ticks.

The effect of temperature on the transtadial transmission of Theileria annulata in Hyalomma anatolicum anatolicum was studied. Variation in temperature (4-40 degrees C) had a significant effect on moulting rate of the ticks and transmission of theilerial parasites from nymphs to resultant adults. The temperatures above 40 degrees C and below 12 degrees C prevented moulting. Maximum infection levels were obtained in salivary glands of adult ticks when the infected engorged nymphs were incubated at 24-28 degrees C. The infection rate in salivary glands was assessed using a methyl green pyronin technique.     

Efficacy of sprays of amitraz against Boophilus ticks on cattle

Cattle infested with all parasitic life-stages of Boophilus microplus (Canestrini) and B. annulatus (Say) were sprayed with 0.0125 or 0.025% active ingredient (AI) Amitraz. The detachment pattern of engorged or partially engorged females indicated that both concentrations of Amitraz caused premature detachment, with at least 90% of all females detaching within 24 h post-treatment. A large portion of the females collected during the first 24 h post-treatment were not fully engorged. The 2 tick species were equally sensitive to both concentrations tested. At 0.0125%, control of Index of Reproduction (IR) of B. annulatus was 98.9% while control of B. microplus was 97.8%. At 0.025% control of IR was 99.2 and 98.0% for B. annulatus and B. microplus, respectively. Amitraz adversely affected size and oviposition of females and the hatchability of eggs laid by treated females. Based on known detachment intervals of females after infestation, it appeared that Amitraz-treated animals were protected against larval reinfestation of both species for ca. 7 days at 0.0125% and for ca. 10 days at 0.025%.     

Studies on Rhinoestrus purpureus (Diptera: Oestridae) larvae infesting donkeys (Equus asinus) in Egypt. III. Pupal duration under controlled conditions.

The pupal duration of Rhinoestrus purpureus was studied under variable degrees of temperature and relative humidity (RH). It was found that pupal duration was affected by temperature but not by RH. An increase in the temperature above 22 degrees C decreased the pupal duration: 26-27 days at 22 degrees C, 16-24 days at 27 degrees C, 13-15 days at 32 degrees C. At 37 degrees C, the pupated larvae failed to pupate and died. The deformity ratio of emerged flies was 25-30% at 22-32 degrees C, but it was directly proportional to RH at a constant temperature of 32 degrees C: 26.1% at 75% RH, 16.7% at 50% RH, 6.7% at 30% RH. It was concluded that the optimum temperature and RH for obtaining normal active flies were 32 degrees C and 30%, respectively.     

Establishment of a laboratory colony of taiga tick Ixodes persulcatus for tick-borne pathogen transmission studies

Ixodes persulcatus Schulze (I. persulcatus) is distributed in Russia and Far East Asia including Japan, and has been implicated as the vector of several human pathogens. In particular, I. persulcatus acts as the only tick vector for human lyme borreliosis in Japan. In order to elucidate the mechanism of transmission of I. persulcatus-borne pathogens, we developed a laboratory colony of I. persulcatus. Ticks were fed on Syrian hamster and engorged ticks that had dropped off the animals were collected and maintained to allow them to molt. Tick rearing was performed in incubator at 20 degrees C with 95% relative humidity and 12-hour light/dark photo-period regimen. We found out that adult females fed for 8 +/- 2 days and had a pre-oviposition period lasting for 7 +/- 2 days. The minimum egg incubation period was 1 month with the hatched larvae feeding for 3 +/- 1 days and molting to nymphs 3-4 months thereafter. Meanwhile, the nymphs fed for 4 +/- 1 days and molted to adult 2-3 months thereafter. For future analysis of gene expression profiles in I. persulcatus, we cloned and sequenced the actin gene (a housekeeping gene), and found that it is 92.7% to 98.6% homologous to the published sequences of related ixodid ticks. This laboratory colony of I. persulcatus will facilitate investigations on the role of tick-derived molecules on the transmission of I. persulcatus-borne pathogens and will be important for identification of potential anti-tick vaccine and acaricide target molecules.     

Transmission of a Trypanosoma sp. to cattle by the tick Hyalomma anatolicum anatolicum

Hyalomma anatolicum anatolicum engorged nymphs and flat adults were collected from two areas in northern Sudan. Various developing stages of Trypanosoma theileri-like flagellates were observed in the engorged nymphs, freshly moulted adults and mature adults partially engorged on rabbits. When these ticks were applied to two calves, one calf became infected with the trypanosome. The parasites were observed for one day in the enlarged lymph node nearest to the tick-feeding site 5 days after the tick application. Subsequently the trypanosomes were re-isolated in vitro from the infected calf. Inoculation of a ground-up tick supernatant suspension from the infected batch of ticks containing 10(4) trypanosomes into a calf did not produce a patent infection.     

Some effects of temperature on the adults, eggs and pupae of Stomoxys calcitrans Linnaeus (Diptera: Muscidae)

Adults could only live and reproduce to their full capacity at temperatures between 20 degrees C and 30 degrees C. At 15 degrees C the females laid no eggs, the adult life span was relatively short and the reproductive capacity of females kept at 35 degrees C was low. The thermal histories of the flies had no apparent effect on their later reactions to temperature in any of the parameters tested. The viability rates of S. calcitrans eggs exposed to temperatures between 10 degrees C and 40 degrees C exceeded 84%, but 45 degrees C was lethal. The optimum temperatures for incubation of the eggs was 30 degrees C. Pupae of S. calcitrans seemed to tolerate temperatures between 20 degrees C and 30 degrees C, but their mortalities increased markedly outside this temperature range. Tests showed that pupal mortalities increased linearly with increasing periods of exposure to a temperature of 15 degrees C.     

The effect of temperature and relative humidity on survival of eggs of the cestode, Monieza expansa (Rudolphi, 1810)]

The survival of Moniezia expansa eggs in the droppings of lambs was investigated at various temperatures in laboratory conditions and on test plots outdoors. The optimum temperature of the livability of M. expansa eggs in laboratory conditions is 5 degrees C; at this temperature 10% of oncospheres survived after 161 days. At the temperatures of 10, 25, 35 degrees C the oncospheres survived 105, 28, 46 days respectively, at -12 degrees C it was 28 days. It was for 21 and 35 days that on the test grassy plots the eggs of M. expansa survived in the droppings of lambs in the summer months of July and August at the average air temperatures of 15.7-18.2 degrees C and relative humidity of 67.7-74.3%. In autumn in September and October, at the average temperatures of 5.8-14.6 degrees C and relative humidity of 65.3-76.7% the oncospheres survived for 49 to 91 days. The M. expansa eggs in the droppings of lambs were able to survive on the test plot. The living oncospheres were demonstrated for 119 days from November 1987 to March 1988, and for 175 days till May by means of experimental infection of intermediate hosts.     

Effect of moving dawn, dusk, or both on oviposition time in domestic laying hens

1. Lohmann Brown pullets were reared on 8-h photoperiods and transferred to 12 h at 15 weeks by either advancing dawn or delaying dusk by 4 h. At 25 weeks, half of each group was transferred to 16 h by advancing dawn or delaying dusk and, 10 d later, each photoperiod-group was advanced or delayed 4 h by moving both dawn and dusk. Individual oviposition times were recorded over 48 h at 25 weeks and 8-10 d after each lighting change. 2. At 25 weeks, there were no differences in mean time of oviposition, eggs laid in the modal 8 h, or in the proportion of eggs laid before dawn between pullets that had been given a 4-h increase in daylength at 15 weeks by advancing dawn and those photostimulated by delaying dusk. 3. Extensions of the daylength from 12 to 16 h at 25 weeks, whether by advancing dawn or by delaying dusk, delayed mean oviposition time by 2 h and virtually eliminated egg-laying before dawn. All groups laid > or = 94% of eggs in the modal 8 h. 4. Moving the complete 12- or 16-h photoperiod forwards by 4 h delayed egg-laying by 0.5 h (relative to dawn), whilst moving them backwards advanced it by 0.7 h. Pullets given 16 h of light laid very few eggs before lights-on, but the divergent movements in oviposition time, relative to dawn, resulted in more eggs being laid before lights-on when the 12-h photoperiod was moved backwards and fewer eggs when it was moved forwards. However, a slower adjustment to the new times of dawn and dusk by the pullets whose day had been moved forward, as indicated by fewer eggs being laid in the modal 8 h and poorer rates of lay compared with pullets that had their photoperiod moved backwards, may explain these differences. It is doubtful that the differences would have persisted after all birds had adjusted their ovulatory cycle, and so any reduction in pre-dawn egg-laying is likely to have been transitory. 5. The only permanent way to minimise pre-dawn egg-laying in brown-egg hybrids is to provide a photoperiod of at least 16 h, though 14-15 h may be long enough for white-egg hybrids and 12-13 h sufficient for broiler breeders.     

Hosts,seasonal occurrence and life cycle of Rhipicentor nuttalli (Acari: Ixodidae)

There are only two species worldwide within the genus Rhipicentor, namely Rhipicentor bicornis and Rhipicentor nuttalli and both occur only in Africa. Rhipicentor nuttali has a widespread distribution in South Africa and the present investigation was initiated to elucidate its host preference, seasonality and life cycle. Rock elephant shrews, Elephantulus myurus were examined for ticks at four localities in the Free State Province, one in Gauteng Province and two in Limpopo Province, South Africa. Cape elephant shrews, Elephantulus edwardii were examined at two places in the Western Cape Province, and a single specimen of the bushveld elephant shrew, Elephantulus intufi was examined in central Namibia. Small mammals of other species were also examined at two of these localities. The majority of E. myurus at two sites in the Free State, at the locality in Gauteng and both sites in Limpopo Province were infested with larvae and/or nymphs of R. nuttalli, while the single E. edwardii examined at one site in the Western Cape Province and the single E. intufi examined in Namibia were infested with nymphs of this tick. Not one of the other small animals was infested. Although larvae and nymphs of R. nuttalli were present on E. myurus throughout the year, the former were generally most numerous during the period March to September, and the latter during May to October. The preferred hosts of the adults are domestic dogs, leopards, Panthera pardus and South African hedgehogs, Atelerix frontalis. Adult females engorged on Atelerix frontalis in 16-32 days and, after a preoviposition period of 2-4 days, produced approximately 170,00 eggs during the following 60-70 days. The average incubation period of the eggs was 59 days. Larvae engorged on E. myurus in 4-10 days and moulted to nymphs 12-20 days later. Nymphs required 11-15 days to engorge on E. myurus and moulted to adults 32-47 days later. Allowing 14 days for the exoskeletons and mouthparts of each of the three parasitic stages to harden before they can attach to a host, the life cycle took approximately 214 days to complete in the laboratory. The length of this period, considered in conjunction with the times of maximum seasonal occurrence of the immature stages, indicates that the life cycle probably takes a year to complete in the field.